FISH DISEASES (very long multible articles)

[jhnrb]

Diseases of Fish

A general overview. Part 1

by Shawn Prescott

-Fish in the environment, stress, & more.

This column, will try and concentrate on the practical considerations relating to the health of your fish, in the real world of aquarium keeping.

Although one may think otherwise, the problems that we face as aquarists, are not exactly the same, as similar fish will face in their natural habitat, although the actual parasites, bacteria, etc. will in so many cases be those, that do sometimes create problems in the wild.

Similarly, in the ever growing field of Aquaculture , there are differences, between this method of keeping fish and maintaining them in the average aquarium. Only by being aware of these differences, and the distinct possibilities that each form can manifest in possible problems , can we begin to both understand the potential difficulties, and take sensible steps to minimize the kinds of diseases or problems that may arise, or hopefully avoid them altogether.

-Fish disease in the Natural state.

The first and major difference between fish in Aquaculture, and the same fish living in Nature, is the sheer volume of water that each fish has access to. This means that although many fish can asymptomatically harbour a parasite, for extended periods e.g. subepithelially , when the parasite is stimulated into a reproductive mode, which typically results in it multiplying itself by hundreds or even thousands of times, the chances of each new spore or Trophont etc, finding a new host, in the wild, is many hundreds of times less , than in an Aquarium or an Aquaculture situation.

Even when we allow that typically about half the species of fish shoal , the bodies of water are so large, & other forms of predation so prevalent, that only a minute percentage of the parasites, new spores etc, will have the chance to re-infect another fish. In large part the same logic applies to bacterial & viral diseases in Nature, However, when man or natural events interfere with the Lakes or Rivers, or the Reef environment, which is unfortunately in contemporary times an everyday event, we hear concomitant reports of fish kills with alarming frequency. The corelation to ecological damage cannot br refuted.

Pathogenic bacteria are everywhere. When we are healthy, your natural body resistance keeps these pathogens at bay. However if for any reason we become weakened, for example by , exposure to excessive cold, or damp sleeping conditions, these same pathogens often flare up, causing us to become mildly or even seriously ill. Similar consequences can happen to fish in their home of rivers, lakes, and oceans.

In Nature when any of the normal background parameters, e.g. temperature of the water, pH, alkalinity, purity ( freedom from pollutants), oxygen values, & more are suddenly changed, from the preferred habitat in which the fish has evolved over eons of time, then the same background pathogens, or parasites, will become very active as the fishes immune system becomes weakened, & unable to provide the amount of suppression to keep these undesirable forms in check. This weakened condition and lowered resistance to disease results from environmental stress.

-Stress : The single greatest cause of fish disease.

Thus a result of environmental stress large numbers of fish are lost as fish kills in rivers, lakes, and other natural bodies of water , & most of you will have read about same in your local press, or even seen it at first hand. Today this happens with monotonous regularity.

In Nature when the prevailing conditions are ideal , only the occasional fish, usually an older one, will become ill. Natural selection usually takes care of such fish, as they are less able to avoid becoming food, for the predators that are omnipresent. This is part of Nature's checks & balances. These weakest had they survived, may have passed on infections to their peer group, but by this process of Natural elimination, this ecobalance keeps down the pool of infection potential, to manageable proportions.

For this survival of the fittest rule applies to the entire natural world, and has the practical effect to ensure that only healthy or relatively robust fish survive to reproduce their kind, or sometimes be captured for the benefit of man, either as food, or as Aquarium specimens. Later in these articles I will compare the drastic changes that take place, both before we ever see the fish, and after it reaches it's new home.

All scuba divers who have the interest and understanding of ecology, report it is rare indeed, to find fish in Nature showing disease signs, such as we often observe in the Aquarium.

Although essentially fish in the wild have a built in awareness of possible dangers, they are also relatively calm, most of the time because they have either many of their own kind around them, as well as a normal habitat . These factors prevent the kind of stress related adrenalin surge , which is the precursor to a weakening of their immune system , in the Aquarium. All to often they have either none, or only one or two of their own kind. Alternatively sometimes in the case of fish that are natural loners, we place 2 of them in an Aquarium, and they display aggression or worse to each other. Either of these unnatural conditions can cause tremendous stress.

The ability to recreate a environmental conditions which minimize stress is of vital importance in maintaining good fish health.

Furthermore, in Nature fish have typically available to them , a large range of organisms, to serve as food, or at the least such organisms as they have evolved to find suitable, as a complete food for their growth, reproduction and good health.

Compare this to the typical diet we give in an Aquarium, which has on average some 10 or more different species of fish, each of which in nature will predate upon different organisms to grow and become healthy, & we feed them one size fits all the same packet of food, day in & day out, with little regard to their individual requirements.

Is it any wonder that the combination of these factors result in high levels of stress ? This, given other factors to be discussed, can & does result in the fatal outbreaks of disease that are the cause of so many Aquarists eventually giving up the art of successful Aquarium keeping.

(Part-1 cont)
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posted jhnrb

 

[jhnrb]

Cont. Part-1

-Natural Normality , in Nature.

Although this may appear to be a redundant play on words, it is worth emphasizing that in the natural , the photoperiod is natural. When the sun comes up it gets light. In Spring, when most fish start to sexually mature it is in response to the natural increase in photoperiod, & with the accompanying rise in temperature in many parts of the world. When dawn arrives it is a slow process, & the same at dusk.

The salient point is that any subtle changes in the quality of the water, is usually caused by other natural changes, e.g. such as the rush of melting snows, which can bring about a normal and useful stimuli to the fish

Compare this to what is typical in the Aquarium.

We configure the lighting to come on at times often to suit our preferred observation times. It is most typically the same all year round, and bears no relationship in many cases, to what is the natural day for the fish. The light comes on suddenly usually within a few seconds, the same when it goes off.

Temperature is controlled by clever thermostats, which keep the water, at what our books & specialists advise us, the same number of degrees from Jan-Dec. No diurnal change as happens however modestly even in the Tropics.

In Nature in Rivers, in most Lakes, and on the Oceans, moving water, renewed constantly, changed & buffeted by wind, rain, tide, & run off from the mountains, keeps a constant purification going. This helps to overcome the natural pollution which would otherwise occur. Furthermore the myriad of natural organisms, utilize so much of the biota that is created along with the excretory products of the Fauna, so as to ecologically prevent in most cases, any excess becoming a cause of fatality to the world surrounding any one species.

Compare this to the typical Aquarium. Some of us do change a percentage of the water in the Aquarium, usually about 10% (if we do) weekly. Many do not even do this.

Instead of a natural ecosystem to manage the various subtle changes that are bound to occur, when we keep our specimens in an artificial habitat, we rely upon filters, often changed infrequently, UV's to kill off as much as can, Ozone to purify, chemicals to supplement what we think needs to be replaced, ( the evidence for such replacement is too often questionable).

It's rather like asking us to feel good in the rather aseptic environment of a hospital ward. Probably alright, (some today even question that), but it hardly leaves the average person feeling that they would like to go there as they felt so good in that atmosphere.

In both freshwater & marine environments there are many forms of natural plant life . Many of these act as part of the food chain either directly for the fish, or indirectly by contributing to other forms of life which eventually are eaten by the fish.

I know of no "plastic" forms of plant that exist in nature, but far too many of our Aquarists seem to think that this artificial media, looks nice and is useful. I personally would seek to disagree.

Furthermore in many of revered Public Aquariums, I have seen the same plastic rubbish replace the real thing, as evidently the professionals who are employed to run these Mecca's of entertainment are not provided with the means by their money masters, to achieve what should be for so many good reasons an essential educational tool.

If one talks "off the record" to many of the Curators of too many Public Aquariums, you may be horrified to hear just how often they have to replace their fish etc. In some cases the record is as bad as Aquarists who have little or no experience. So much for conservation of Nature.

Again the reason is in many cases, that to create a stress free environment is one that requires a great deal of expertize, planning & the funds & personnel to make it work, on a long time basis. When this is absent, whether it be in a Public Aquarium or one in our home, then stress is a typical consequence, & fatalities are to be expected, as disease manifest itself.

Once again the major reason is the stress factor put upon the fish, which is not in accord with their experience in Nature.

Finally in Nature, because as I have said above, natural selection sorts out the weak leaving the best to reproduce, one tends to have stronger specimens.

Much more has to be done to both understand, & provide realistic answers to the kinds of problems here outlined, & we will return to this subject later on in the series, in some more detail.

END PART-1

Continued..

 

[jhnrb]

Part-2

Diseases of Fish: Part 2
by Shawn Prescott

(IN PART-1) I attempted to contrast the major differences between fish that live in a "natural state" & those kept by man, either in Aquariums, or in Aquacultural situations.

Some may feel that I was in some way against keeping fish for pleasure, and in case there are others who might have felt likewise, I should take this opportunity to say unequivocally, that I have enjoyed keeping Aquarium fish, for almost half a century, and took up what is in fact my profession, because of my abiding interest in them, which has thankfully never waned.

It is essential in my view to understand the "norms" of fish in the wild, as a precursor, to being able to take the required steps to minimize the problems of disease that so often break out when fish are kept by man, in Aquariums or otherwise.

Later on in this series, I will deal with the specifics of disease, but before doing so, I would like to point out some of the similarities, as well as the major differences, between fish as kept in Aquaculture, & those which we keep in the Aquarium. This with special regard to the influence the differences have upon disease for us Hobbyists.

In Aquaculture it is normal to rear just one species in raceways, cages or tanks. Occasionally farmers practice Polyculture ( the keeping of 2 or more species side by side), but this is not common, & even when it is the practice, it is seldom more than 2 species. It is a rare Aquarist that keeps only one or two species, in his or her Aquarium.

For the Aquaculturist, this means of course he has a much higher risk if disease should break out, as many pathogens, whether parasitical or bacterial in Nature, often have a preference for a species, which can under circumstances which are favourable then spread very quickly. Contrarily the Aquarium usually has many species which mean that some diseases at least will not spread as fast, and give the Aquarist a chance to get the problem under control.

Because of the enhanced risk, good Aquaculture practices, require the fish farmer, to pay constant attention to water quality, disinfection procedures, and the continuous observation of his stock, as any lapse can bring about serious losses, which after all are his livelihood. For this good reason today more and more farms are employing trained Biologists to manage the farms, and try to keep the risk of disease under control.

Today many more Aquarists, also pay close attention, but as it is a Hobby and not a source of revenue, for nearly all of us, the degree of close observation & the amount of control equipment is often much less than on a professional farm.

Another difference in many but not all farms, is that in cage culture, or such things as Trout culture, in some areas, the water body is constantly changing, taking away pollution, and renewing the quality of the water. There are of course farms that work on closed systems, but even here it is typical to make up some 2% or more of new water daily. This prevents the accumulation of undesirable "metabolites" which are most often Nitrates, Phosphates, Proteins, and more. This cleansing of the water body in Aquaculture is vital, as any diminution of the water quality, can very quickly give rise to stress, which can quickly help bring latent parasites, viruses, or bacteria, into a chronic state of infection.

Many Aquarists do of course also change water, many do not do so, or if they do it is infrequent, and anyway, even the best of us, do not do so daily. This means that we must rely on more sophisticated control methods, such as Protein skimmers, Ozone generators, UV purification, Biofilters, and much more in the form of water additives etc. For those of you who have taken the trouble to understand the reasons for such technology, and can measure the effects, this can and does yield some excellent results, such as wonderful Reef Aquariums, as well as beautiful planted fresh water Aquariums.

Regretfully, poor advice, sometimes at the dealer level, lack of time, or inadequate understanding of the often quite complex interactions, can lead to heavy losses of fish, and too often to the "retirement" of otherwise keen Hobbyists, who feel that our pastime is too difficult.

The purpose of my articles is to try in some small way, to show that this need not be so.

You have already heard me refer to STRESS several times as possibly the single greatest cause of fish developing disease, & before proceeding to the more specific details of disease, I would like to give a real example of something that I did with my team some years ago in the UK, which I think emphasizes this point very well.

At that time I had an Aquaculture consultancy business in the UK, but also ran our own Labs, & had adjacent to the premises a fairly large Aquarium store.

We observed the following phenomena, many times over. Typically we would receive our shipments of fish on a Thursday, so that we would be well stocked for the heavy weekend trade. We had several beautiful show tanks from which we normally never sold, & whenever we got an especially nice specimen, or something that was different we would place this fish in one of the show tanks as an attraction. I would point out that these tanks were set up for long periods of time, were maintained as professionally as possible, as they were our "Advertisement" tanks, and we often did not add a fish for several weeks.

I would mention that I am talking about Marines in the example which follows.

We made the observation that the following day after adding the "new" fish, that one or more of the "old" fish would have broken out with signs of "white spot" Cryptocaryon irritans, whilst the newly introduced fish was quite all right & showed no signs of any problem. This was contrary at that time to what we somehow expected. Also it occurred so often, that we began to develop a new theory at that time as to the cause.

In pursuit of this idea, we decided to sacrifice a fish in one of the tanks which we had had for some 8-9 months, and which was in perfect condition. To this day, I still feel rather guilty about it, as it was a magnificent Powder Blue Tang ( Acanthurus leucosternum). The reason we chose this fish, was that we had had at least 4 examples of this species breaking out previously, with the said white spot.

In our Lab, we proceeded to do skin scrapings of the unfortunate fish, and very quickly we found encysted spores of the parasite which were obviously lying dormant and doing no harm. It should be noted that by definition a parasite has a vested interest in its hosts well being, as any change in that status, which may affect the fish, can also have undesirable effects on the parasite.

CONTINUED

 

[jhnrb]

(cont. Part-2)

Having proven to our satisfaction the almost ubiquitous presence of this common parasite, we then proceeded to rationalize the outbreaks I referred to as follows:-

Fish as most Aquarists have observed are very territorial, they also quickly get to know an Aquarium, and also the other inhabitants, many species will stake out a place of their own, especially Clown fish andother Damsels, but also many others. When a new specimen is introduced, many fish become agitated, they feel that the newcomer, will take their favourite spot in the tank, compete for available food, or "steal away" perhaps their friends.

Such alarm can often be seen in school if we can recall when a new and challenging new face appears, especially if he or she is handsome, strong, aggressive, or clever.

We manifest this emotion sometimes by feelings of jealousy, or counter aggression, or displays of bravado, which may not even be natural to us. Should there be a major challenge such as occurs many times, when a bully appears, adrenaline courses through our bodies to help us cope with the stress.

My team and I, became convinced that something very similar was happening when we introduced the new fish, to those who had "rights of occupation". Some form of chemical messenger undoubtedly ran through the veins of the resident fish, and this would "wake up" the dormant parasite who would translate this message in such a manner as to say to itself, that perhaps my host will not be around much longer, something is the matter, and this STRESS messenger would cause the parasite to immediately go into the reproductive phase and burrow out of the epidermal wall of the resident fish, giving rise to the typical "white spot" markings.

Although such a theory is hard to prove, pragmatically we were able to almost do so, as once armed with this conception, we always added the new fish afterwards in subdued light after having changed a couple of hours before some of the rocks in the tanks and other such position markers. We also left the lights out with the tank covered for a day or so. We did not eliminate the problem, but the number of times it happened afterwards was a small fraction of what had been an almost invariable occurrence before our experiment.

The lesson to be learned is that many things can cause stress, and that we should always seek to lessen this by understanding the underlying reason, and that if we do, we can greatly minimize the problems that all to often occur.

Therefore I hope you will bear with me when as I proceed in this series, you will find I will return frequently to the matter of good husbandry, which is effect the practice of avoidance of stress, as far as the art of Aquarium keeping allows.


Some rules which are worth repeating for those who may not know, or have perhaps forgotten or become careless, all of which will reduce stress & therefore the eventual possibility of disease.

-When buying fish from your local dealer, try & ensure that the specimen you select, has been in his establishment for a least a week, & see it is feeding. Perhaps pay a deposit on the understanding you may change to another fish, should it not have been there long enough, assuming you really want it. The ask the dealer to keep it a few more days, & ensure you may chose another fish if it does not "measure up" Most good dealers will assist as they want you as a customer.

-When taking a fish home, ensure that the clear plastic bag is covered by an opaque cover of some kind. Nothing will scare a fish more than being trapped in a clear bag, from which it cannot escape, & seeing all the strange sights to which it is then subject

-Ensure that you equalize the water temperature, as well any pH differences SLOWLY, over at least half an hour, by the slow addition to the bag of the tank water, & floating the bag first to balance the temperatures.
Add the fish in as subdued a light as possible, and DO NOT turn on the lights for the rest of the day, to view the fish, which although a natural inclination, should be resisted in the interest of longevity for your new fish, and even the old ones.

-Ensure in both fresh & salt tanks, large numbers of hiding places, so that the fish can find a new "home" and feel secure from any perceived enemies.
Avoid tapping the glass, to try & bring the newcomer out from any hiding place, when it has adjusted it will display itself to your content.

-Ensure if necessary with the advice from your dealer, if the new specimen(s) you are considering, are compatible with those you already have. Some fish are naturally antagonistic to others, whilst in Salt water, two similarly sized Angelfish of the same species will often fight to the death.

-Do not overstock the holding capacity of your tank, crowding will induce stress very frequently, & can cause a total wipe out in some circumstances.

-If you have burrowing fishes, such as Kuhli loach in fresh water, wrasses or some gobies in salt, ensure that the type of gravel you are using is suitable, as some are sharp & can quickly cause abrasions which will lead rapidly to the demise of the fish, & perhaps spread to others.

-Avoid putting on lights in a darkened room, suddenly, as this unnatural shock can cause many fishes to jump out of the tanks, Swordtails are great at doing this. Either only illuminate from a room which is already lit, and if you can try to attach to your lighting system some form of Rheostat control which will bring the lights on and off SLOWLY, just as the sun comes up and goes down in nature.

The practice of these basic rules, and no doubt others, will help towards the goal of keeping fish more in harmony, with the natural condition, and this is one as I pointed out last month, that has less virulent diseases, that can occur in Aquaculture & the Aquarium for the reasons I gave .

Next I hope to begin the process of looking at the various ways that disease can manifest itself, and begin the long process of trying to understand the many potential problems, and how we can address at least some of them.

END PART-2

Continued....

 

[jhnrb]

Part-3

Disease: Part 3
By Shawn Prescott

Readers will recall that in the last two PARTS, I attempted to show the important contrasts in stress, & therefore the potential for disease between fish as they are in Nature, & those that are kept in captivity, especially those that are kept in Aquariums.

Today throughout the world, fish are beening bred in captivity for food in most cases, but also for our Hobby. It is a fact that today, a very large percentage of the fish we enjoy watching in our home Aquaria, have been bred in captivity. This is a far cry, from the early days of the Hobby, when almost 100% of the fish which were sold, came from wild caught supplies, in many countries.

Although there are similarities, between the environments in which Aquaculture maintains & breeds its fish, to those we create for the home aquarium, there are also important differences, & in order to better understand, how fish may be stressed & become ill, it is useful to be able to make such comparisons, which are set forth in Table 1. Below:-

FISH LIVING IN / IN NATURE / IN AQUACULTURE / IN AQUARIA
Many kinds of fish /Yes / No / Varies
One type of fish / Never / Usually Almost / never
High density / No / Yes / Can vary
Ideal water Yes / Mostly / not always / Variable
Good husbandry / Not applicable / / Usually Variable
Subject to predators /Yes / Only at juvenile stage / Seldom, but can be
Natural food / Yes / No / Rarely
Water changed often/Yes /Depends on method / Variable
Subject to stress/ Yes, but only natural /Stress by crowding & more / Depends upon skill of Aquarist

I think it is informative, to look carefully at this short list, as it makes us focus on, what are the similarities, & even more importantly the differences which occur. I maintain that these differences account in quite some measure for the diseases, & the factors that induce our fish to become sick, in too many instances.

-Diversity.

We see that in the rivers & oceans, that fish are present, in great numbers & in many species. Although predation is a natural form of existence, the various species have evolved methods to deal with it, such as camouflage , shoaling, natural habitats which give shelter, to name only a few, therefore the fish does not feel stressed, as part of its existence, unless exceptional conditions arise.

In Aquaculture fish are raised in a number of different ways. These include earthen ponds, cages, raceways, ( of many types of construction), sea cages in open sea, & protected bays, as well as entrapped artificial divergent streams, & Lakes, as well as several other variations of these. For the most part in Aquaculture the fish are the same species, though there is a trend in some areas to Polyculture, ( the rearing of tow or more species, which are compatible, in the same environment). Here at least although stress can & does arise for other reasons, the stress that can be caused by an incorrect choice of species in the Aquarium does not arise.

In Aquariums, it is usual to find a few to many kinds of fish, the discerning Aquarist, will ensure their compatibility, but often by wrong advice or being unaware he will put a fish or two, into the Aquarium, which will become very aggressive to others, & will cause stress to other fish, which can quickly result in disease breaking out.

-Density.

In Nature, the oceans are to a large extent unlimited at least as far as the numbers of fish are concerned. Thus although the numbers in some shoals may be enormous, there is never any problem of overcrowding or the consequential deterioration of the water quality.

In Aquaculture, the name of the game, is to get the absolute maximum numbers of fish, per given size of tank, cage , pond or whatever, as is commensurate with rearing the fish to point of sale, without them getting ill. The expert fish farmers, spends much of their effort, in trying to achieve just this. However from time to time for many different reasons, engineering breakdown, storms, changes in water quality, the fish may be & are sometimes subjected to tremendous stress, & when this happens, the window of time to rectify this is short, & limited.

In Aquaria, except with those novice Aquarists, whose enthusiasm exceeds their current knowledge, today most Aquariums, are not overcrowded. When this rule of giving reasonable space to the species we intend to keep, & ensuring that we have made due allowance for the eventual size they will become, the question of density causing stress should not be a factor. Remember though, especially newcomers to the Hobby, it can easily become a factor. Thus choose your fish thoughtfully, & with careful research into the compatibility with the fish you already have.

(CONT.)

 

[jhnrb]

Part-3 (cont)

-Water quality.

In Nature the water quality is for the most part a constant, with a few exceptional conditions, which may be caused by run off, or flooding etc. Here the fish has evolved in its ideal habitat, & it is very rare, for any stress to be caused by water chemistry, or temperature changes, other than those which are natural. However increasingly & most regrettably, there is yearly more reported "Red Tides" & similar type occurrences, which are not fully understood at this time by Science. Much informed opinion leans towards the explanation, in at least a large number of cases, that mankind's alteration of the environment by run-off's , by untreated sewerage, by oil spills, by damming of rivers, & so much more. These "Red Tides", are in many cases, highly lethal, sometimes to the fish themselves, other times to humans who may ingest species exposed to these tides, which often cause toxins of rare potency to be formed.

The economic losses, due to the shut down, of collection especially shellfish, during these outbreaks, by Governments, to protect public health, runs into millions of dollars, so assuming that we as humans are in some measure responsible, the consequential losses in economic terms are considerable.

In Aquaculture, the water quality, is in many cases, totally controlled by the farmer, although in sea cages, it can be similar to nature, though even here some problems have arisen. Because this vital parameter is so important, in most fish farms, water changing is a part of the everyday routine. Not withstanding this, many are the occasions when some vital chemical or other parameter, will change, invariably for the worse, & this can threaten the stock of the farm, often within a horrifically short period of time, which can amount to less than an hour in extreme cases.

In Aquariums we today have the technology to control water quality to a high degree. Notwithstanding this, for a large number of good reasons, the water quality from Aquarist to Aquarist, varies in large degree, form superb, to abysmal . Among the myriad of reasons, are, lack of good advice from the dealer, lack of adequate funds to purchase some of the essential equipment, poor water quality at source, & there are several others. The high quality Aquaria, will encounter a much lower level of diseases, whilst one can be sure, that the lower levels of water quality, will have the highest incidence of disease outbreaks. One can also say with certainty that many of the Aquarists who quit the Hobby, do so because they have lost too many fish due to disease. It will help everyone to be successful, if we can try together to reduce disease, & improve where necessary the water quality.

-Good husbandry.

In Nature, this matter is not relevant, as the quality of the fishes life is natural, & it will normally thrive.

In Aquaculture, this is the essence of what fish farming is all about, & woe betide those farmers, that become careless, or do not keep up with the most successful techniques. Any improvements in technology rapidly spread in today's world, & quickly are reflected in the final price of the fish. For this reason most fish farmers, are constantly tending their stock & pay great attention to their well being.

In Aquariums, this is certainly also true for the elite among our Aquarists. I would say, even the majority among those of you reading articles like these. Regrettably this is not always the case among too many of the millions of Hobbyists out there. Lack of time, paucity of knowledge, combined with the fact that for too many, Aquarium keeping has & always will be, a passing fancy, to go along with other whims, like roller skating, baseball, the latest movie, etc. It is here that the quality of the water tends to vary downwards, with all the attendant consequences of disease, & final abandonment by the enthusiast for the Hobby he ardently espoused for a few weeks or months.

-Predation.

In Nature, fish are constantly predating on other fish, or plankton, algae or whatever. This is part of the natural cycle of life. They in turn, with a few exceptions like large whales & sharks, are also subject to predation. Most fish have a built-in awareness of the dangers, & over eons of time, have evolved techniques to lessen the risk. Among these are shoaling ( safety in numbers). Background camouflage , habitat security, development of toxins to ward of predators, association with other species, that lessens their risk, & more.
Because all of this has happened naturally, they are seldom in a heightened state of stress, although they have this consciousness that causes them to take cover, when they think danger may approach. We have all seen shoals of fish, move in sudden uniform fashion, to another direction, which is almost always, an instinctive reaction to a perceived danger, which they hope to avoid. By & large then, stress & its consequential increase in disease factor, is not very high in the natural environment.

Aquaculture , for the most part, with good management, is seldom subject to predation, unless in the case of ponds or lakes, etc., there are natural predators that may prey upon the stock. These can & sometimes are a serious nuisance. Among the worst offenders, are Herons, Pelicans, Snakes, Otters, Monitor Lizards, & others. However any serious fish farmer, is aware of these risks, & technology today, is capable in large part of finding answers to this problem . There are still some types of predation that we need to find answers to, & these are the subject of constant & ongoing investigations. One such in Aquaculture especially in Salmon culture is a form of predation that is in reality a parasitic disease. Sea Lice, have emerged as a substantial predator on stocks of salmon, which are now farmed in many countries of the world. These cause enormous economic damage, & although some progress has been made to control them, it is not yet adequate.

In Aquariums, predation is often caused by the Aquarist being unaware of the incompatibility of the specimens he has chosen. In Reef tanks many Invertebrates, even though sessile, are capable of causing injury leading to death, of another species, when they are placed to close together so that they touch. Many species of fish will attack another kind, often incessantly, & this with some major & beautiful species of Angelfish, is especially so, when the fish are the same kind & of similar size. Other species like Butterfly fishes will live on their natural food, i.e. certain corals, to the horror of the owner, who has spent hard earned money to acquire a prized specimen. Not only does this cause losses, but the fish which are attacked rapidly develop major stress symptoms, as they unlike in Nature to escape the problem, being confined in an Aquarium. These symptoms are too often the reason that a disease will break out, which then quickly passes, to others in the tank, who although not being attacked cannot escape the spread of the infective organism(s), that ensue.

It is therefore vital that when we select species of fish or invertebrates for our Aquarium, we should ensure that we carefully taken note of what is compatible, not only with the new species we are about to buy, but also with those we already have in our tank.


(CONT)

 

[jhnrb]

Part-3 (cont)

-Natural food.

In Nature, there is only natural food, so this is hardly ever a cause of disease, as each species seeks out the forms of nourishment most suited to its requirements. There is today an increasing danger however that as mankind has "successfully" overfished almost all of the major commercial species, that the "natural" chain of food, now for the first time, having its knock-on effect, may cause some changes in the ability of many species to have an adequate diet. This overfishing effect has already had undesirable results, with much bird life, when their preferred food species has been tremendously diminished , e.g. sand eels on the Puffin population.

The environmentalists, must also be allowed to make their studies & inputs into the decisions about fishing quotas, & we have a long way to go, before we can safely say we understand it all.

In Canada, the economy of the State of Newfoundland, was seriously impacted when the Government having for years got their statistics wrong, were forced to close down the major fishing grounds on the St. George's bank, with the loss of some 30,000 land based & seafaring jobs. This economic loss is still affecting the local economy.

In Aquaculture, natural food is seldom applied. Almost all diets, although invariably containing some fish meal ( a major limitation at the moment on the unbridled expansion of fish farming), are produced in factories that make up a balanced feed, that contains state of the art, know-how about the various requirements of the fishes dietary needs. An interesting but minor exception to this was recently revealed on one of the bulletin boards of the Aquaculture industry. I do not recall if it was Scotland or Ireland, but they contributor found that they were getting a very high conversion ratio, ( less than 1:1, this means that they were getting more food in production of the salmon, than they were feeding to them, on the face of it impossible). On investigation they found that the droppings from the fish were causing a "bloom" of phytoplankton, which attracted vast quantities of mysid shrimp. The salmon fed on these shrimps, & grew at a much higher rate than had ever been observed for the applied ration of food. I feel sure that variations of this may become a part of future fish farming.

There has been in Aquaculture, because of the nature of the food, some important & costly disease/problems, among them it has been found, that some manufacturers, did not have adequate quantities of Zinc, in their diets, & this caused blindness with important losses, until rectified. Other diets have been found to lack on or more of the various vitamins, or amino acids, most of which are as vital to the healthy growth of fish, as they are to all other types of living creatures. It is seldom practical to feed natural live foods to the fish in Aquaculture, but it may be pleasing to you as Aquarists to note, that when there are exceptions, it is usually from the ornamental side of the industry, that such are used. Of course in the early larval stages of Aquaculture natural live foods are used all the time, most especially in the form of Brine shrimp( Artemia), without which there would be no Aquaculture as we know it.

Aquarium use of live food is highly variable. Most good shops carry one or more varieties of live foods, & a large number of serious Aquarists buy such on a regular basis, & some others, culture or collect their own. The use of such foods is important , & in some cases vital, as there are fish, who will never touch a prepared food, such as leaf fish in Freshwater, Seahorses, & Lion fish in Saltwater & many others.

Without such additions to their diet, many fish will progressively weaken & become prone to disease. This can be avoided, by choosing a suitable live food & feeding it regularly, although it is often difficult to ensure without a great deal of trouble, that the fish that need the live fish most, get to it. Too often other faster fish, have eaten all or most of it, while slow moving fish like those mentioned, have had almost none of the same.

Another alternative is either to avoid such obligate live feed species altogether, or keep such only in a tank to themselves. Sometimes Hobbyists will do this, & ensure that a number of pregnant female Guppies are always present. Such females will eat almost any food, whilst the continuous supply of offspring will provide a constant live food diet to those that will eat nothing else. Hobbyists should be aware, that Guppies, can be kept in full saltwater, & will even breed, if the "change over" is done gradually over a few days. Whilst large Lion fish, will also eat the parent stock, Seahorses will not look at an adult female, but will eat newly born fry.

Aquarists, should take careful stock of their fish, along with the eating habits of same, & ensure that the diet, is adequate & balanced, otherwise over a period, stress will develop, & with it disease that can affect all the fish in the tank.

-Water changed often

Finally in Nature the water is constantly changing, & only as said earlier if pollution occurs is their any problem on this account.

In Aquaculture water is often changed on a regular basis, or if in cages in the ocean, is subject to constant change. Notwithstanding this, from time to time even in the sea, the sheer volume of fish in a given area, has caused some massive problems, & this in various ways. Good fish farmers, are aware of this problem, & today techniques to measure & control the problem are in place in the more important countries.

In Aquariums this is a major variable. Most Aquarists are aware they should change the water on a regular basis. For reasons of time, money, "theories" that contradict the popular wisdom, as well as the insistent adverts, of some producers of additives, many change rarely or insufficiently. Without doubt, this factor is responsible for many unexplained "sudden" outbreaks of disease, in tanks that had apparently had no problems. A good rule of thumb, in Aquariums that are NOT overcrowded, is to change about 7-10% of the water volume weekly. This in both fresh or salt water tanks.

These then are the major differences between the environmental pressures that fish are subjected to, in the 3 different ways of their existence. By looking carefully at these, & understanding, what helps & what does not, then by applying these principles to our Aquaria, I believe major benefits can result.

For those of you, that are fed up with me rambling on, about the background to disease, in part 4 I will begin to examine the various forms that disease can take. Along with the treatment, or preventative action that is sometimes possible

end part-3
(CONT)

 

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Part-4

Diseases in Fish
Part 4
By Shawn Prescott

Well finally ( not before time, probably some of you would say), we will begin the long journey to examine the many ailments that fish are prone to. The lists are so extensive that sometimes one wonders how fish survive at all, given the countless "enemies" just waiting to strike them low.

Not withstanding this, most fish given good husbandry & attention will thrive & be a constant pleasure to those of us, who like to replicate a small piece of nature in our own homes.

The diseases and problems that can afflict fish can be broken down into the following categories:-

1) Parasitic
2) Bacteriological
3) Viral
4) Nutritional
5) Toxicological
6) Environmental
7) Other.

we will begin our investigation of diseases, by looking at the first major group, that is the parasitic species, that are endemic to so many of the tropical fish, which for the most part today are bred on farms.

-PARASITES OF FISH

GENERALLY:

In considering these parasites, the Hobbyist should be aware that some parasites essentially need an intermediate host, in order to be able to complete their life cycle. In several cases such an intermediary is a snail, or some form of Invertebrate such as Daphnia, or other similar organisms. In such cases, by eliminating the intermediary we can bring the spread of the infestation to a halt.

In the wild probably a majority of fish are host to one or more parasites, but for reasons addressed in previous articles, they seldom become a major problem or cause of mortality. In fact there is considerable evidence that in some of the more prevalent parasites e.g. White spot that exposed fish can develop an immunity against further attack

Whilst it most cases it is recommendable for the Hobbyist to purchase young specimens, ( as they will live longer, & more easily adapt to the confines of his/her Aquarium), such specimens are also more prone to succumb to attacks by parasites having less size, and body weight to resist the damage that many of the parasites can so easily inflict. For this reason, any purchases, should be carefully inspected, to ensure that there are no "blemishes" of any kind, on the desired specimen, & the buyer should also ensure that no fish are bought from any tank in which any fish are manifesting unfavourable symptoms. Parasites once present in a tank can in so many instances spread rapidly with devastating effects, & a fish that has been exposed & yet appear to be perfect, can break out within a day or so, spreading its parasites to others in your Aquarium.

For those of you that have the possibility , it is advisable to keep all newcomers in a separate quarantine tank, when first purchased. This will give one the chance to ensure that nothing untoward, will be transferred to the principle Aquarium, as it is counterproductive to try treating a fully setup community system, when disease breaks out. The period of such quarantine, bearing in mind the life cycles & latent period of so many of the potential problems should be 3 weeks. This is the period used by Government edict in Australia, which is one of the few countries so far, to require all imports of Tropical fish to be so held, in Government approved holding facilities.

Therefore if you do take the prudent step to quarantine all new purchases, it is wise to make certain that they are kept for at least two weeks, if not three, before introducing them to their new home. I realize that such goes to a large extent against the "I want it now" , type of society we live in today, but the " I want a cure, that is 100% effective, works in one day or less , & causes no headaches" DOES NOT EXIST, so caution can pay off in spades, as they say.

It is also important to note, that parasitic infestations, often do not kill directly. However because of the damage they cause to the tissues & vital organs of the fish, they frequently cause secondary opportune infections of bacteria & fungi, to invade the fish, bringing about a rapid death of the host, & often spreading the new infection throughout the Aquarium.

In order to avoid the potential spread of any infestation or infection, all nets, or utensils of any kind that may used with your fish, should be kept in a sterilizing solution between uses, & rinsed thoroughly before & after use.

-Methods of diagnosis: (Parasites)

Although it is possible to come to a reasonable diagnosis, by carefully noting observed signs (symptoms or indications), which in fact is part of the purpose of this series of articles, it is most useful if the Aquarist can manage to have on hand the following tools to aid & help confirm their findings.

An inexpensive stereo microscope. This should have magnifications of 10-40 times to enable one to observe the majority of the parasites. Such microscopes can be bought new nowadays for around $500, but many are available from secondhand dealers, for about a third of this price. If buying a used instrument ensure that the optics & mechanical system are in good working order prior to commitment.

A few glass or plastic Petri dishes of suitable size in which one can lay the fish in a small amount of water whilst making observations.

A simple fine pair of tweezers, which can be used to "pick of" some of the larger parasitic forms for closer examination, without keeping the fish too long out of water.

Some glass microscope slides for making skin smears.

A simple plastic rod (thin about 3mm daimeter) which can be used to gently pry open the gills of the fish for examination.

A fine pair of scissors which may be needed to excise a small piece of fin tissue, for closer examination.

A glass pipette, which may be used to aspirate (suck), some material from the gills or elsewhere for further examination.

Whilst these materials are not essential, they do make accurate diagnosis, far more certain, & any Hobbyist who has invested serious money in their Aquarium(s), would be well advised to try & obtain the above items.

-Diagnostic procedures.

Whenever fish are observed with some abnormal signs or behaviour pattern, it behoves one without delay to try & make a determination of what is the cause.

Even if one suspects that the cause may be parasitical, bacterial, or viral, the first thing that should be observed & noted are ALL the water parameters. Often an adverse change in the quality of the water can induce latent potential infections to break out, so that even with a correct diagnosis it will be extremely difficult to treat the problem without taking steps to remedy the cause of the water in-balance. Some signs such as hanging at the surface, are common to the observed indications for some diseases, but also to water quality problems like Ammonia toxicity. Thus even though we will pursue all the recognized procedures for determining the cause, first ensure that the water parameters are where they should be for the species you are keeping.

Poor water quality can bring on many parasitic diseases. Reliable & easy to use test kits should be used to ensure that the quality of the water is in accordance with normal parameters.

If for any reason they are not, take the appropriate steps to rectify the problem, ensuring that any correctional changes are made slowly to avoid further stressing the fish.

Assuming the water quality is within normal values, then one should proceed as follows:-

1) Note down all external observations that are abnormal.

-Behaviour

One should examine any signs of abnormal behaviour, such as unusual swimming patterns, refusing all food etc. etc.

-Body

Look especially for colour changes, bleeding or ulcers, swellings etc.

-Skin

Try & observe any cuts or lacerations, scales protruding etc.

-Eyes,

Observe if any Exopthalmia (popeye) is apparent, or cloudiness etc.

-Gills

Examine the Gills & note if the colour is a normal bright red, or if it shows unusual colour or other markings.

-Fins

Note if the fins appear normal, or are rotting, or show markings etc.


(CONT.)

 

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Part-4 (cont)

When all the unusual signs have been noted it is then sometimes possible with the aid of a good text book or computer programme, to make a determination . However just as in human and animal medicine, we like to have absolute confirmation, & for this reason some of the verifications which follow should be attempted, this assuming you have the above mentioned equipment. If one does not, then the specific details of each disease, should be kept, as a reference source, along with any other good book that one has, & you make your best shot, at the problem, without the "proofs" which we will now talk about.

(ADVANCED AQUARIST)

-Skin smears.

Probably the easiest & often the one that will "prove" the diagnosis fastest & most conclusively at least as far as parasitic infections are concerned is the skin smear. In order to do this one takes a clean microscope slide & simply presses it gently over the area on the fish that one suspects is a source of the problem. One can also "run" the edge of the slide along the infected area, with a little pressure, & this will almost always release some of the epithelial matter along with some indication in many cases of the causative organism.

A word of caution. In a fish that may have had a wound or similar for quite some time, ( over a couple of days), there may already be secondary infections taking place, of a fungal &/or bacterial nature, it is important to be aware of this when taking such a smear, & these are best done in the earliest stages for best results.

Once the smear has been made, it should have a drop of clean water should be added to the slide with a pipette & an examination under the microscope should then take place. Be careful when adding the drop of water that only a small amount is added, otherwise the vital material to be examined can all to easily "flow" off the slide & make the examination more difficult or useless.

Again a good reference book, or computer programme will be needed for most Hobbyists to enable them to recognize the causative organism which may then be observed.

-Fin Biopsy

If the fins show any abnormality, one should take the fish, holding it gently but firmly in a wet clean cloth, & using a fine pair of scissors, cut a small piece of tissue from a fin that is showing signs of abnormality. Cut between the fin rays, so that only tissue is removed, in this way minimal damage to the fish will ensue. Proceed to examine the sample in the same way as with skin smears.

-Gill examination

Hold the fish as mentioned above, & prise open the gill covers with the mentioned clean plastic rod. Insert a fine pipette & aspirate (suck) a small amount of tissue, from the gill lamellae taking from any part that may appear abnormal ( dark in colour, pale, with small black or white dots etc). Let this material drop onto a clean slide as before & proceed to examine same.
Wet mount of a Gill Biopsy showing I.mutifiliis trophozoites.
Photo courtesy of Dr. Ed. Noga. NCSU.

Should one need to proceed to do post mortem examination of a dead fish, then it is advisable to use a qualified laboratory, & take samples from some of the internal organs as well as the outer body. For such examinations detailed methodology which requires some special preservatives, as well as certain specimen holders & more must be used, otherwise the chances of it arriving in a fish disease laboratory in a useable form are remote. Laboratories tell us that nearly half the samples they receive cannot be used as they have not been prepared correctly. Qualified laboratories will instruct persons what procedures must be followed.

Armed with your notes on external signs & adding to this confirmatory examinations as indicated it should be possible to make accurate determinations for at least the majority of parasitic infections.

In the following articles we will deal with some of the major diseases as are typically found in the Aquarium, beginning with by far the most prevalent.

END Part-4

(CONT)

 

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Part-5

Diseases in Fish Part 5.
Shawn Prescot

-Cryptocaryon irritans

Causative organism: Ciliated protozoan parasite viz:- Cryptocaryon irritans
Synonyms ( alternative names):- Marine white spot.
Geographic distribution. World wide.
Water type . Salt water.
Typical signs of infection. Cryptocaryon irritans.

Water. Less than optimum water quality, such as a lowering of the pH level, or high Nitrate or Phosphate readings can lead to an outbreak.

Behaviour. Fish will evidence lethargy, and may from time to time, try to "scratch" of the organisms, by rubbing against an object of some kind in the Aquarium. Distress is visibly obvious.

Fins. Fins often become clamped or folded. White spots (after which the disease is popularly named) usually appear often at first on the pectoral fins. As infection progresses, very large numbers of these spots of size 0.5-2.0 mm will spread .

Body. White spots appear on the body, & will if untreated spread so that almost snow like appearance will spread over its entirety. Some haemorrhaging may appear in later stages of the disease.

Eyes. In medium to advanced stages of an outbreak, the eyes typically become clouded, & when very heavy blindness can ensue.

Gills. Gill examination will show large numbers of the organisms .

Skin. (smear). Should show ciliates once an infection has become established. Secondary infection with fungal is commonplace once major invasion of the skin has taken place, adding to the problem.

-Life cycle
Transmission is direct, with no intermediate hosts. Cryptocaryon is an obligate parasite, which means that it must infect a host fish in order to complete development.

The life cycle of Cryptocaryon can be conveniently divided into four basic stages. Susceptible marine fish become infected with the active free-swimming stage, called the theront (or tomite).

The theront is incapable of feeding within the aquatic environment and therefore has a limited time, less than 12 hours, in which to contact and invade a fish, otherwise it will exhaust its energy reserves and die. If invasion is successful, the theront penetrates below the skin epithelium, possibly aided by digestive enzymes such as hyaluronidase, and transforms into the parasitic stage which is known as a trophont. The trophont actively feeds on the fish's tissues, twisting and rotating as it does so. It grows rapidly, doubling in size approximately every 24 hours. By 48 hours, the parasitic trophont is just visible to the naked eye, appearing as a small white spot on the fish. By the third or fourth day of infection, the trophont will have attained 3 to 5 millimetres in length and at about this time it exits from the fish. Although the trophont is equipped with rows of beating cilia it is too bulky to swim away from its host and instead it sediments to the substrate. ( Within a few hours, the trophont has firmly attached to the substrate and rounds up to form a thick-walled cyst. The cyst, also known as a tomont, is the reproductive stage which will eventually give rise to between 100 and 300 infective theronts, thereby completing the life cycle. Of course, not all theronts are successful in locating and infecting a host, even under ideal conditions only about 5-10% succeed. Nevertheless, within an closed environment, Cryptocaryon can increase in numbers by approximately tenfold every six to eight days. This enormous reproductive potential explains the sometimes rapid build-up of infection levels in any closed system..

The cyst is the only stage of Cryptocaryon which is known to reproduce; there is no conclusive evidence to suggest that the parasitic trophont stage can multiply within the fish's epithelium.

-Prognosis

There is no reason why mortalities should take place, as to reach lethal levels this parasite usually takes some 7-12 days. Observant hobbyists should take remedial action, at an early stage & if this is done, and the results CAREFULLY monitored than a successful eradication of the problem is possible. Care must be taken, to ensure that no latent parasitic tomonts are still present, so that the problem does not recur.

-Treatment

In those Aquaria, where fish only are present, Copper based remedies, are very effective, although those chelated forms of Copper of which there are several have not in the writers experience given good results. The claim that you can use heavy doses of such Coppers, without harming the fish may be true, regretably the same argument applies to the parasite. With the true Copper treatments that are effective it is vital to use a reliable Copper test kit, & in the first few days of treatment this must be done several times daily, as the Copper in a new tank to be treated, "binds' to the glass the rocks, & just about anything else, so that the theurapeutic level drops below the recommended amount, & under this the parasite is able to complete its life cycle. Treatment should be continued for at least 7 days after all signs are absent, to ensure that no latent tomonts are waiting the chance to reinfect.

In Reef Aquaria, however no Copper treatments can be used, as they all will have fatal effects on almost all Inverterbrate life. This leaves the Hobbyist with the alternative of catching his/her fish, & treating in a separate Aquarium. This is time consuming & can often ruin the appearance of a tank that has been carefully nurtured over a long period of time.

Fortunately Fish-Vet ® has today a product called Ecolibrium ®, which allows successful treatment of this scourge, and is harmless to all Invertebrates. No test kits are needed & it biodegrades after a week, when treatment is ceased.

Another technique which can be used to help accelerate the eradication of the problem, is by giving the fish baths in either fresh water, or at a salinity of less than 10 ppt. The parasite cannot tolerate the change in osmotic pressure, though I am not sure if it will affect the tomite stage as much as it will the free swimming trophont. This technique has been used very successfully in Aquaculture with those species of fish that are highly euryhaline (= able to tolerate wide variations of salinity). Our Aquarium fish for the most part will tolerate baths of up to a half an hour, but one must ensure that the pH & Temperature are similar to the Aquarium water. Also do not do any other task whilst the bath is taking place, as some fish will react worse than others. If major distress is observed, the fish must be returned to the Aquarium. I have used this method to reduce the level of infection, & it has proved beneficial, though never absolute. It's greatest advantage is when the fish shows evidence of a high level of infestation, & one wishes to bring it down somewhat before starting more conventional treatment.

There is some evidence that there are 2-3 different strains of Cryptocaryon irritans , nobody to my knowledge has yet made a definitive analysis of such, but the empirical evidence would seem to indicate this. One observation made by many observers, is that the treatment that in one case is quickly and totally successful, in another either is not, or takes much longer to have an effect. One pragmatic point that the writer has used with success is those persistent cases, that either do not appear to react to conventional treatments , or do so much more slowly, is that it seems that the parasite is in some way linked in its life cycle to the photoperiod. In order to disrupt its usual timing of division, reproduction etc, I have found it helpful on occasion to leave the lights on , for some 2 days, & then do the opposite whilst at the same time covering the tank with a dark blanket or suchlike. This "manipulation" of the light seems to have a deleterious effect on the parasite, which coupled with the medication used often results in its elimination. I do not advise this however in the more usual straight forward cases.

(CONT)

 

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Part-5 (cont)

A special observation:- The writer has observed with some of his co-workers on many occasions, that Crytocaryon irritans often breaks out under the following conditions. The Hobbyist will have a tank with several specimens all of which are free of any signs of the parasite. A new fish will be introduced & the following day, "white spots" will be observed in a great many cases, NOT on the new introduction, but on one of established inhbitants. This happened so often so years ago, that we made some experiments on apparently "disease free fish". Most especially some powder blue, & yellow Tangs.

Cyst of C.irritans

We found on these fish, which had been free of all problems for more than half a year, that when we did some skin scrapings, that we found evidence of trophonts under the skin. Evidently these had not found it necessary to reproduce & leave the fish, as no sign of disease had occurred over a long period of time. With this evidence we explained the phenomena just mentioned as follows:-

A parasite by definition has a vested interest in co-existing with it's host. As long as no unusual disturbance takes place, it will continue it's idyllic existence , in harmony with it's host. However when a new specimen is introduced to the Aquarium, often the established inhabitants become quite excited, feeling that the newcomer will in some way, take their "space", eat their food, or even team up with their favourite fish/companion. This causes some form of chemical message to course its way through the fishes system, in much the same way, as adrenalin causes us, to become excited if we get a fright or suchlike. This chemical message, in some way alerts the parasite, which in effect says to itself, "Oh boy!, maybe I should get out from here, & look for a new host". The consequences are seen the next day, when it bores out from the host, leaving the telltale white spots.

To counteract this reaction, as much as possible, it is advised when introducing new fish to an established Aquarium, to do the following.

1) Introduce all specimens with the lighting as subdued as possible in the room, & with no lights on in the tank, continue this at least until the following day.

2) Change if possible one or two rocks, so that the existing fish are concentrating their attention on the change in the habitat they are used to, & not on the newcomer(s).

Of course it is also sensible if the Hobbyist has the facility to quarantine the new specimen, as they also can and do, introduce the parasite to the tank . This should be done if one has a separate quarantine tank, for at least a week, & preferably for 10 days.

END PART-5

(CONT)

 

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Part-6

Diseases of fish Part 6
By Shawn Prescott

One of the most commonly found group of parasites in fresh water tropical fish which give rise to the disease known as Trichodoniasis,, this parasite has also many variations in the marine environment. (Trichodina, circle shaped skin Parasite on Gill filament.) So far no major report of serious outbreak in the Aquarium marine hobby has been notified, although a few minor cases are recorded.

In Aquaculture there have been some major outbreaks, & a Hobbyist should therefore always be aware that such is a possibility. In salt water we will talk about the parasite Unonema marinum.

-Salt water parasite Uronema marinum.

This parasite is the salt water variant of the fresh water species known as Tetrahymena. It is a free living ciliate species, that is quite often a "visitor" to marine Aquariums & can if unchecked cause quite severe losses. As an interesting aside, a colleague working with Tuan fish culture in Australia, has found this parasite to be her greatest problem, and with these species I understand it invades the brain, causing many serious problems.

It affects several varieties of popular Marine Aquarium fish, among them are Tangs, especially the Yellow Tang, Pomacanthid species , Seahorses, as well as some Centropyges, many species of Butterfly's, yellow headed Jawfish among others.

Life cycle. This takes place by simple mitotic division, but there seems to be quite a body of evidence that in marine Aquariums at least, that high organic loads appear to favour the reproduction of the ciliate.

Typical signs of infection. Uronema marina.

-Water. Less than optimum water quality, especially high loads of organic matter, which may show up in excessive Nitrate and/or Phosphate measurements, as well as an undesirable BOD measurement.

-Behaviour. Fish will evidence agitation in the early stages of an infestation. Rubbing and scratching are to be expected as the fish tries to dislodge the irritation. As the disease progresses, extreme lethargy ensues. Eventually the fish will rise to the surface, hanging there, in an attempt to get air, as it gills become more and more parasitized . Heavy breathing may be observed at this stage. The fish may try hiding away from other fish and observers.

-Body. In the early stage, a certain fading of the natural colour of the body colour will manifest itself. This will appear as a kind of fading of the colours. As the disease progresses, evident necrotic erosion of the body becomes evident, & haemorrhagic lesions will become apparent.

-Eyes. In medium to advanced stages of an outbreak, the eyes typically become clouded, & when very heavy blindness can ensue.

-Gills. Gill examination will show large numbers of the organisms .

-Skin. (smear). Should show ciliates once an infection has become established. Secondary infection with fungal is commonplace once major invasion of the skin has taken place, adding to the problem. Excessive slime will be noticeable on the skin.

Histo-Pathology. Smears taken form the gills as well as the skin, usually show many hundreds of the ciliates which are about 40 x 20 microns in size. Evidence of infection can also be expected by examination of the ureter, as well as the kidney. As mentioned earlier evidence has now arisen of infestation penetrating the brain as well.

Prognosis:- Outlook is extremely variable. Heavy infestations usually cause such necrotic damage that mortality ensues, probably by secondary infections. The references to treatment in the literature are sparse, & I will relate from my own experience, as well as the excellent short book by Gerald Bassleer (in German), as little else is available. I believe it is possible with scrupulous attention to the details to "defeat" this scourge, which can literally destroy an Aquarists prize specimens rather quickly if not controlled.

Treatment. The preferred treatment which has worked for me, & is also referred to among others by Bassleer, is to use prolonged fresh water baths. These should extend from 15-30 minutes & must be repeated for several days to ensure a good result. The fresh water MUST be the same temperature , pH etc as the water in the Aquarium, to avoid extra unnecessary stress, & under no account should the Hobbyist, try to do any other task during this time. No telephone calls etc. The fish must be closely observed for undue stress (most fish will keel over but will not be too greatly stressed if the points mentioned are adhered to. However if the fish is in an advanced stage of infection then this method will certainly kill the fish, not only from the stress, but also because if there is already major necrotic damage, then the change in osmotic pressure that will kill the parasite, can cause the fishes body fluids to "osmose" out to the water of the container, & the result will be its demise. The treatment works well in early cases, & especially so, to prevent fish that have been exposed to the infestation becoming badly infected.

The Aquarium must be "cleaned" of all excessive detrital material as there a correlation between the amount of such & the proliferation of parasite. If possible infected fish should be placed in another Aquarium until recovery appears to be under way. The parasite seems to be unable to tolerate the change in osmotic pressure, & simply stated it bursts, if one is able to keep following through. The problem can be that some species of fish, as well as variation among individual specimens, also occasionally will cause such distress as to harm the fish. This is mostly avoided by keeping a close eye on things.

Bassleer, also recommends using Malachite green or a combination of Malachite and Formalin. Logically this should work, as it does on may other related ciliates. However he states no dosage, & considerable caution should be used, if choosing this regimen, as no other commentator has referred to it. He also mentions the use Methylene blue, and especially mentions a combination of Chloramphenicol with Nifurpirinol. Again for these no dosages are given, but probably he has found they work, as one would expect them to be efficacious against secondary infections, which so often are the ultimate cause of death.

As most of the likely species to be infected in the Hobbyists tank, are among those that are expensive, it is most useful to have some knowledge of what to look for, in this parasite, as I have often saved almost all my fish by discovering it early, when treatment has the greatest potential for success. I have unfortunately witnessed all to many cases, where the outcome was an almost total loss.

This month before finishing I want to take up a matter that whilst not strictly a disease, is one that causes many losses in Marine Aquariums. The subject is Cyanobacteria, aka Red Algae.

I get many calls about it, However, I have for a few years been investigating the underlying reasons for this phenomena.

There are several references in the literature to the alleged fact that Cyanobacteria are supposed to thrive when the Phosphate levels are excessive. Many times Hobbyists have contacted me to say, that they are plagued by "Red Algae", but that their Phosphate levels are either zero, or almost so.

I began a few years ago to make some preliminary investigations, as I had a suspicion that perhaps the cause was not PO4, (inorganic Phosphate), but in fact PO3 (orthophosphate or organic ). At that time, some 10 Hobbyists were kind enough to send me samples of their water & in every case I tested the water showed as they said almost no PO4, but substantial PO3 values.

If anyone has any idea how the PO3 becomes transformed in the biological interactions that take place in an Aquarium, please post an article on po3 as well as any references in the literature. This would be important in trying to find some methods of prevention, rather than cure. As the several Phosphate "sponges" or similar on the market, only remove PO4, such would be a most useful contribution to the Hobby, as so many beautiful Reef Tanks are ruined by this "slime".

END PART-6

(CONT)

 

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Part-7

Diseases of Fish
Part 7
By Shawn Prescott

In article-7 I propose to deal with a Marine parasite called Brookynella.

-Brooklynella

Brooklynella hostilis is found as a parasite in Marine Aquaria far more often than is commonly recognized as it tends to be overshadowed by the more frequent & well known parasites viz. Cryptocaryon irritans and Amyloodinium (Oodinium) ocellatum.

It like so many others is a ciliated protozoan which in many respects resembles its counterpart in fresh water Chilodonella. When conditions become favourable to its reproduction, very rapid multiplication takes place , reproduction occurs by simple binary fission, & such massive reproduction can & does cause fatalities , which is brought about by severe weakening of the host fishes.

The literature reports many differing species of fish as being susceptible, & the first reports of this parasite were related by accounts from some of the more prominent (at that time) Public Aquariums, such as the New York Aquarium Steinhart, etc.

Typical signs of infection
Brooklynella hostilis

-Water
There is little doubt that fish exposed to lowered water quality , and in particular the stress of elevated Ammonia /Nitrite levels such as are brought about in shipping, can induce an outbreak of this parasite. All the literature seems to confirm this.

-Behaviour

Fish demonstrate lethargy, will "toy" with their food, appearing to eat & then spitting it out. Respiration becomes difficult as the Gills become heavily parasitized , & can easily be observed.

-Body

A "faded" appearance of small areas becomes apparent , & such areas spread outwardly as the infestation progresses. Sloughing of the epithelium will occur in later stages.
-Gills

Gills will become massively parasitized and a smear or other examination of the gills should easily determine the cause of the infestation.

-Skin

As the "sloughing" occurs increasingly large areas of damage can be seen, as the skin becomes broken down by the parasites activities.

-Histo-Patholgy

Parasite can be confirmed by skin or gill smears from suspected fish. Parasites are mobile and range in size from 60x80 microns to 40x48. In shape they are heart or kidney shaped ( see illustration), and they have typically ventral organ for attachment to their host.

-Treatment

The literature has very little on effective treatment, & the authors disagree on the application of Copper as treatment, (Stopskopf's book recommending its use, whilst Blasiola stating categorically it does not work). In this authors experience I have to agree with Blasiola, I have never found it to be effective against Brooklynella.

The combination of the following treatments & techniques have worked for me, on several occasions with varying degrees of infection, to eliminate the parasite, but I have had to employ at least 2 of the methods, & often all four. With careful attention the parasite can be brought under control( eliminated), but one should be aware there is no " 24 hour" simple cure. Be very suspicious of anyone telling you that they have such a remedy.

1) Giving a "dip" in freshwater of the same temperature & pH as the Marine tank, for about 15 minutes ( careful observation must be made, during this time, to avoid distress, & the fish removed, if major problem is observed).

2) Giving a bath in Sea water with Formalin added add at a dosage of 1000 ppm for some 15 minutes.

3) Adding an Acriflavine product (such as Fish-Vet's Revive) to the tank water for a period of 2 weeks after the above treatments.

4) Taking severe steps to ensure that water quality is optimum along with the TOTAL removal of any detrital matter .

I would mention that G.Basleer mentions in his book that Quinicrin gives a good result, regrettably he does not give any figures for dosage, or any contraindications.

If any secondary infections with by bacteria are observed then the use of an antibiotic would be useful. The use of UV to help prevent secondary infection should be employed.

It is useful to point out to the Aquarist who is intending to buy fish, that the judicious way to avoid to problems that this noxious parasite can bring to your Aquarium, is often best managed, by ensuring that your dealer has the fish in his tank for some 2 weeks prior to you taking it home. Most fish that will break out due to the stresses of transport , with this parasite will do so within this time.

To be fair to your dealer, you should show goodwill, by making it a conditional purchase, i.e. offer to pay for the fish, or at least part of it, provided he keeps it, & it is alright after the period of time mentioned has elapsed. Brooklynella is not an easy parasite to eliminate, so the effort to avoid it, is worthwhile.

I suspect that some of you as you read what would appear to be a depressing catalogue of parasites just waiting to attack your precious fish, may become disheartened somewhat, especially if you have had the misfortune to suffer one or more attacks in your early days in the Hobby. Therefore at the risk of been repetitive let me again emphasize that fish have an amazing ability to withstand infections, their immune system like most Veterbrates is well developed, & only when the conditions that we prepare for them or that they are exposed to, before we receive them are substandard, can we anticipate outbreaks which will adversely impact their health & our enjoyment of them.

Thus once again, everything you can do, to maximize the conditions in your Aquarium as well as ensure that you buy fish that have been properly collected, ( not with Cyanide for example), held in conditions at all stages of the collecting/shipping processes, can you reasonably expect to have little or no problem.

I can hear some of you saying to yourselves, "how can I know, how the fish are collected /shipped etc". This is not easy, but careful reading of the literature, observing how your dealer handles his fish ( does he make any effort at quarantine etc), asking about his suppliers, (does he import directly, or buy from a wholesaler, ) does the wholesaler quarantine the fish etc. All of this will give you a far better idea of what to expect with the fish you buy. Furthermore, you should carefully observe how many dead or sick fish are evident in the dealers tanks, good dealers, who buy from good suppliers, will have far less than those that do not. All of this will enable you NOT to eliminate the risk, but greatly reduce it.

END PART-7
(CONT)

 

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Part-8

Diseases of Fish
Part 8
By Shawn Prescott

-Salt Water Coral Fish Disease. (Amyloodinium ocellatum aka
(Oodinium ocellatum. ) This is the form of the parasite that gives rise to the disease known as Coral Fish Disease.

There are many similarities between this marine variant of the parasite and the fresh water forms.

So that the salt water Hobbyist should be take into the account the differences and not make an error in diagnosis I will define some of the special features of the salt water form .

In the fresh water forms O. pillularis & O. limneticum , the organism's primarily attack the skin, & then spread to the gills. In the saltwater form O. ocellatum the parasite seeks out the gills & may then spread to the skin.

Oodinium ocellatum attaches to the gills of the fish, this interferes in oxygen transpiration causing suffocation.

By the time the latter takes place however, the gill damage is almost invariably so severe, that the typical "first alert" I have already mentioned of seeing a fish "gasping" on the bottom of the tank, is unfortunately all too common. The damage to the gills, causing haemorrhaging, swelling, and intense necrosis, which lead to an inability of the fishes gills to pass sufficient oxygen, which leads to suffocation & death.

The reproductive phase of the free swimming dinoflagellate takes place optimally in water of a pH of 8.0- 8.2 with a density of 1.012- 1.021 and with a higher than desirable organic load, especially of Nitrate.

Typical signs of infection. Oodinium ocellatum

-Water.
High organic load, with less than optimum water conditions, can often serve as the precursor for an outbreak. It thrives in Temperatures of 25-30 C , & salinity of 1.012-1.021.

-Behaviour.
Gasping for air, with very rapid respiration, most typically on the floor of the Aquarium, but sometimes at the surface, are nearly always observed. In the early stages of an infection, "flashing" or rubbing & scratching are often indications as the fish tries without success to rub off the irritating organism. If the Hobbyist can pick up this "flashing" action at an early enough stage there is a chance he /she can prevent mortality

-Gills.
Excessive mucous will be a sign that the parasite is attacking the gills, & a smear as often described previously should easily confirm this. Heavy necrotic damage is easily observed even with a good hand magnifier.

-Skin.
The skin will show "gray" patches which if examined closely will manifest a "dust like" appearance, giving the skin a "velvet" look, which has given rise to an alternative name for the disease. Some haemorrhaging may also become evident.

-Histo-Pathology
A scraping of the skin, or gills will invariably show signs of the dinospores , which have a very easily recognized outline. Once the infestation has been confirmed remedial action should take place right away.

-Prognosis.
The disease as with its freshwater counterpart, usually springs itself upon the awareness of the Hobbyist, with the first fish or more, giving their last gasps as said on the bottom of the tank. At this stage seldom can such fish be saved, & the outlook for them is very poor. If however there are still large numbers of uninfected fish, or some only lightly infested, then if prompt & suitable action is taken , it should be possible to save the others.

-Treatment.
The remedy for the saltwater form is rather difficult. Copper has often been indicated as a drug of choice, but has many problems in its use, as well as being dangerous to the fish in even small overdoses, & especially if even minor damage has already occurred to the gills of the fish. In Reef tanks it cannot even be considered.

Methylene blue, has been used with some success, as it has the advantage of been an excellent oxygen transporter, which aids the transpiration of oxygen to the fishes gills. Methylene blue however is highly toxic to Nitrifying bacteria, & its use, should be confined to a separate quarantine tank only. If used a 1% stock solution should be made (1 grm in 1 Litre of pure water). Use .8ml of this stock solution for each US Gal of water to be treated.

Acriflavine & related compounds have proven very effective, & this as in salt water has given the writer & his co-workers the best consistent results over the years. (Fish-Vet makes a product called Revive based on this experience, which has an excellent track record.) This product can be used in a fish only and /or a reef tank, & will not impact adversely the Corals etc. Carbon & Protein skimmers should not be used during the treatment period, as they pull out of the water, much of the useful material, but may be used to clear the tank once treatment is completed. Lighting should be subdued during the treatment period.

In both the fresh-water & saltwater form of the disease, the reproduction and hence the eventual intensity of the infestation is closely related to the temperature. Lower temperatures will slow down the reproduction of the parasite, & thus possibly give the Hobbyist a little more time to take effective remedial action. The Hobbyist must evaluate however the species he/she has in their tank, and the tolerance for a lower temperature that their collection of fish, is likely to withstand.

The reverse use of temperature may also be employed, by increasing the Temperature by quite a number of degrees as indicated above. This has the effect of speeding up the parasite's life cycle, & with the use of a suitable treatment as well as employing a prolonged photoperiod, often causes the parasite to burn itself out. If such a technique is employed then the lowered oxygen level of the water must be compensated for, by increasing the aeration substantially.

END PART-8

(CONT)

 

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part-9

Diseases of Fish
by Shawn Prescott

In this article we will start to examine the many bacterial infections to which are Aquarium fish are prone.

Before dealing with the specifics, I would like to reiterate what I stated at the outset of this series, as it is most important for all of you, who wish to prevent or cure any of these potential hazards.

Bacteria including the non pathogenic as well as pathogenic forms are usually present in small numbers on most fish. They in normal situations seldom cause any problems, as the fish’s own quite adequate immune system is more than capable of fending off any infection which may become chronic.

However if parasitic infestations become severe, & major necrotic damage is done, to the skin, fins, gills etc of the fish, then the opportunistic bacteria will often invade the eroded area, leading quickly to a major infection, which too often can be fatal.

This situation can arise in another way, without the presence of parasites . That is when for any number of reasons the fish become stressed. This lowers their resistance, & latent bacteria, can then quite quickly manifest themselves, causing a problem for you the Aquarist. Such infections can in some cases, then spread to other fish, though this is not invariable.

The reasons for stress are worth remembering. Among them are poor handling in the many steps of the way, from the farm or capture, to the Importer, then to the store, and finally to you the Hobbyist. Coupled with rough handling often comes poor water quality , as well as the placing together of incompatible species. Any or all of these, will cause trauma, stress, & a lowering of the fish’s natural immune system, with the consequent breaking out of a disease, that in other circumstances may never occur. Thus it only sensible, if you wish to minimize your risks, that you try to ensure that NONE of these factors will apply to your specimens. It may take a little more trouble, but your reward will be fine healthy fish, and none of the heartbreak of seeing a prized specimen, succumbing & even dying to a problem, that might with a little foresight have been prevented.

Unfortunately with all the best intentions, many of you will still encounter from time to time, such problems , and we will need therefore to have an idea of the various bacterial diseases, which we may encounter, and what signs we should use to identify them , as well as remedial techniques, to be used where such exist.

It should be noted that for the purposes of identification that bacterial diseases are divided into two broad categories. These are Gram-negative and Gram-positive. This means that prior to the specific tests that determine the particular pathogen we divide them according to a simple Gram stain. This Gram’s stain is a complex formula used today throughout the world as a first determinant to identify the major bacterial group.

When swabs containing the bacteria are stained with this formula if the tissue colonies of bacteria stain Purple or Blue, then Gram positive bacteria are present, if Pink or Red is the result then Gram negative are present.

The majority of bacteria we will meet in Aquaria, are of the Gram negative type. The importance of this to the Aquarist is that the treatment is usually different for the two forms , and obviously to have any success we must know what disease we are dealing with BEFORE selecting any treatment.

It is also a fact, that in many cases of opportunistic infections, that mixed colonies of bacteria will be found, as they in many cases, will enter the wound, created as I already stated, by a parasite the ideal place for an invasion. Thus we often will opt for a broad spectrum treatment, if we suspect that this may be the case.

A practical problem, that you as Hobbyists will encounter, is that in the first instance, it is not easy to find Veterinarians who have the specialized knowledge of fish pathogens to identify the precise infectious agent. Secondly the economic value of any given fish, for the most part, will never be worth the cost in pure economic terms of the fees a Laboratory or a Veterinarian, would charge for such work. This work requires much specialized equipment, and knowledge , as well as some expensive consumables.

Furthermore assuming that you find such a qualified person, or laboratory, and are willing to pay the asked for fees, the time element may render the answer academic. Most tests will take a few days to get the absolute answers, during this time, in some instances at least your fish may have passed on to another world, or at a minimum, will be more sick, than when you began.

Thus we need to be aware to the extent that is possible of the indications of the bacterial infections that we may encounter, and take such steps as are prudent, to try in most cases to remedy the problem. You should be aware, that those labs or Veterinarians who can do such work, are typically working with large Aquaculture farms, or river boards, where there is a considerable economic value involved, often running into a million dollars or more, of fish, which can be endangered. Thus these specialists do exist, but for the most part they are far removed from the problems which the Aquarist may encounter, even though in a great many instances the disease can be the same bacterial form which they encounter in their daily work.

I now propose to select certain quite commonly encountered diseases, and give the reader the most encountered signs, so that hopefully with this information, along with the aid of their trusted local dealer, some extra good literature, or a professional advisor, they can possibly both identify and apply suitable treatments.

(CONT)

 

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Part-9 (cont)

The first pathogen we will deal with is Mycobacteria.

This Pathogen has a couple of forms viz. Mycobacterium marinum, and Mycobacterium fortuitum .

Both of these are in fact Gram positive and they give rise to a form of piscine Tuberculosis.

Most species of salt water fish are susceptible, and it is VERY IMPORTANT for the Hobbyist to be aware, that this is one of the few forms of fish disease, that is communicable to humans. This transmission, when it takes place, usually manifests itself with large melanomas on the arms of the fish-keeper. They can spread, and are very difficult if not impossible to eradicate. Any Hobbyist suspecting therefore that they may have encountered this disease, is strongly advised to were surgical type gloves, when handling any fish, to sterilize all nets & other items that may come in contact with the fish, and notwithstanding all these precautions, to “scrub up†after handling them. These melanomas usually take some 3-4 weeks after exposure before manifesting themselves, so it is essential that the Hobbyist be aware of the danger, and take precautions, as the writer is aware of a few cases, in which the unfortunate Hobbyist has got these disfigurements for life.

The observable signs are :

-Lethargic movements
-major wasting
-Loss of scales & Fin tissue
-“Popeyeâ€
-skin ulcers often with small haemorrhages
-edema.

Histologically in doing a postmortem we may expect to see, a number of white to gray nodules on the liver, kidney or spleen. One often finds necrotic black tissue eating away at the internal organs.

-Prognosis
In severe cases it is seldom possible to make an effective treatment.

The disease is a slowly progressive one, and can take quite a long period of time, before it becomes fatal. It does not seem to spread from one fish to another, though there are cases recorded where this would appear to have occurred.

Treatment, as recommended by Stopskopf, is a combination of doxycycline & rifampin. These will not however be available from your local store and would have to be obtained from your Veterinarian with a prescription.

To try and ensure that the problem does not spread to other fish, you must take steps to ensure that your water quality is of the highest standard. Although I am against the continuous use of UV sterilizers , in this case I would approve their use. Furthermore any obviously far gone fish should be removed from the main tank at least , or even humanely “put downâ€. Normally if such methodology is carefully adopted then the problem can be brought under control.

Most observers believe that the causative organism is ubiquitously present, so that it is very difficult to eliminate it entirely. However if effective husbandry is employed, along with good filtration as well as regular water changes , coupled with a varied diet which should include some live food, and the addition of a good vitamin mix, the problem can be eliminated as a cause of mortality. This will not apply of course to any fish that have developed the infection to such an extent that they have wasted away , and in such cases as I have said it is better to put them kindly to sleep, this can be done, by placing the fish in a small container with water and adding an Alka Selzer tablet. Do NOT dispose of the carcass by “flushing†it down the toilet, as this is a prime way to spread the disease. Place the fish in some foil and dispose of it with the solid waste of the household. Also do not feed the dying fish to larger carnivorous fish, as this an excellent way to spread the infection.

END PART-9

(CONT)

 

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Part-10

FISH DISEASE
Buying a better fish.

Now to the more general topic of how to avoid “importing†disaster to your aquarium. Many hobbyists I hear from seem to have little faith in the advice of their dealer. This begs the question why if this be so, do they continue to buy from them. Sometimes geography will be the reason, but certainly this cannot always the answer.

Impetuosity is without doubt a major reason, as is the fact that we expect instant perfection with little input on our side.

-one. to observe when selecting a dealer, to find out how long they have been in business. This may be a little unfair to new entrants to the industry, but usually a store that has survived the first 3 years or more will make it, whilst failures, as in most kinds of business, will take place within the first 1-2 years. It would appear self evident, that those that make it, are usually more knowledgeable than those that do not. Also in many cases more ethical.

-two, does the store or/and its employees appear to have a good background in the science of fish keeping, or do you get the impression that they are trying to sell you some equipment or fish just to make a sale,.

-Three, do they take the time and trouble, to find out what kind of equipment you already use, and which species of fish you currently have in your set-up. This is important, because I find often, that hobbyists, have purchased incompatible fish, which then cause stress to each other, and subsequent disease outbreaks.

-Four, Does the store have some really magnificent show tanks, not only a reef tank, but also a planted fresh water aquarium, and in fact at least on example of how an aquarium should be , of the type YOU are interested in. It is notable to me, that in Japan, and many parts of Europe many stores appear to have as many “demonstration†not for sale tanks as they do, tanks from which they do sell. This does two important things for you the buyer. It enables you to have an idea of just how beautiful an aquarium can be, when maintained properly. It shows you that the store must know what they are talking about in how to keep such a beautiful show tank.

-Five, Are the tanks in the store clean, the water sparkling clear, and is there, as there should be a TOTAL lack of any dead or sick fish in the tanks. NEVER buy from a store where such evident examples of problems can be seen. Every store will have some sick fish, but the good stores, will firstly quarantine all new arrivals and treat them for a few days, and certainly will pay close attention to all and any signs of problems and remove them for treatment. Sometimes I have seen good stores that be treating a tank, and will have a paper or other screen over a tank during this period, with a sign saying “not for sale†or suchlike. This store is taking it’s responsibilities seriously and is likely a serious store.

-Sixth Is the fish or fishes you intend to buy eating properly. Have you seen them rush greedily for some food. Fish that are sick, or shortly to become so, very typically are sluggish or indifferent to feeding, and this is often an excellent warning sign.

-Seven. Has the fish you wish to purchase been in the store for at least a week? Most problems occur either immediately on arrival or in the subsequent few days. If a new arrival especially appeals to you, and you are worried that the store may sell it before you return, then ask to leave a small deposit ,as a sign of good faith. All good store owners will be happy to do this for a regular customer, and if it should get ill , or needs further treatment, you can either wait, get your money refunded, or apply it to another purchase. In every case you will avoid almost certain problems.

-Eight. Is your aquarium in perfect condition, and are the fish you wish to buy, unlikely to overload the carrying capacity of your tank. Each tank can only sustain so many fish, and if in your enthusiasm you wish to capacity beyond what the tank and it’s support system can safely allow, then catastrophe is guaranteed. Remember that in nature the fish have hundreds of times this “living space†and a constant natural replacement and/or natural eco- system and filtration to back it up.

-Nine. Not always possible, but highly recommended. Try and have a small quarantine tank ( 10-25 gal) which you keep with some form of active biological filtration, etc, and keep the new arrival in this tank for 3-4 days after purchase. Should the worst occur, you can treat easily and effectively, without the trauma of pulling down or destroying your main aquarium, in an attempt to catch all the inhabitants, or having to treat in the main aquarium, which at the least will use far more medication. Ensure that in the “hospital†tank, there is some stones or other hiding places, as otherwise the fish may easily become stressed due to fright. Normally I would not medicate, only if something appears that requires it, as all medications have some stress factor in themselves, but on occasion cannot be avoided.

Finally, read up on the fish you are keeping and wish to keep. Many fish have some special requirement in their diets, yet to many hobbyists, buy a packet of standard food, and feed that religiously every day, so that the essential missing factor in time assumes a critical importance and the fish weakens. By finding out through reading good literature you will become aware of what the needs of your fish are, and sometimes this will apply to water chemistry, temperature etc as well. Information is readily available in this day and age, so use it, and have happier and healthier fish.

END PART-10

(CONT)

 

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Part-11

Diseases in fish
Everyday questions and some important answers
By Shawn Prescott

Answers to some frequently asked questions:

-Question.1) My saltwater fish are infected with a parasite, they are showing spots, but I do not know if it is marine “Ick†aka Cryptocaryon or Coral fish disease aka Amyloodinium?

Answer: Firstly one should be aware that the “spots†in marine “Ick†are much larger and whiter than those for Coral Fish disease.

Furthermore, Amyloodinium, usually kills the first fish at least within a matter of hours of being observed. Further casualties can be expected in short order, if untreated. Cryptocaryon, typically takes 2-3 weeks progressively getting worse every couple of days, but seldom kills quickly.

In Coral Fish disease, the spots are small, often grey or yellow in colour, and cover the fish so that under light at the correct angle, they will resemble a sandpaper effect. Furthermore as they most usually in severe attacks, congregate also on the gills, one often will find an infected fish, gasping on the bottom of the tank (sometimes at the surface), desperately trying to get air. The parasites impede by their sheer numbers the passage through the gills of oxygen, as well as doing severe necrotic damage to the gills tissues.

For those of you who wish to read further into these two common parasites, so you may distinguish the difference, I would refer you to the archived issues of the magazine. In Feb. 1997 you will find a full article on Cryptocaryon irritans , whilst in May 1997 you will find an article on Coral Fish disease aka Oodinium or more correctly today Amyloodinium.

As each call to us is frantically directed to know, what to do, I may here give some pointers about treatment.

As many of you know, we ( Fish-Vet ) produce a product formerly called Ecolibrium today called “No-Ickâ€. This product will eliminate Cryptocaryon irritans from fish, and is safe to use in a Reef Tank as it will NOT harm any Invertebrates. You can obtain this product from any of our dealers..

As already mentioned, the progression of this disease, is such that one usually has time to call the store and order the product. Of course the quicker one begins treatment, the surer the cure, and the less damage to the fish.

However in the case of Amyloodinium, the progression of the disease is so rapid, that unless one has a medication such as our “Reviveâ€(also Reef safe) ready on hand, the chances of saving most of your fish is not high. Thus if you have in your tank a considerable investment in fish, it is certainly worth the investment to have a bottle handy so that if you do experience this devastating parasite, you have the odds stacked in your favour. “Revive†can cure this scourge, in about one day, as it is lethal to the parasite.

Question 2). I think I have more than disease in my tank, possibly Cryptocaryon irritans , as well as Amyloodinium, and even a bacterial infection. Can I use “No-Ick†( Ecolibrium), and “Revive†simultaneously?

Answer : I am sure we get asked this question several times each week. This is our considered reply, based on thousands of case histories.

First determine what the problem is. It is rare to have both parasites simultaneously in your aquarium. However if you are quite sure that you do, then treat first for Amyloodinium, with “Reviveâ€, as the progression of this infestation is so fast, that all the fish will be dead unless treated immediately.

Do NOT use “No-Ick†and “Revive†at the same time. This can lead to problems of interaction under some circumstances, and we cannot determine, the subtle differences that will cause a problem in one set-up and not another. As “Revive†only needs 2-3 days to totally eliminate the Coral fish disease parasite, and as Marine “Ick†takes much longer to cause fatalities, you have time to pursue this course of action.

It is important with both medications NOT to use your skimmer, or any charcoal filtration during treatment, as either or both of these, will remove some of the active ingredients, and thus make them less effective.

After treating with “Revive†for 3 days, turn on your skimmer, and use a good brand of activated charcoal in your filter, for about 12 hours, to remove any residual medication. Then add “No-Ick†and treat as directed. Again turn of the skimmer, and remove charcoal from the filter, until the treatment is completed, and the C.irritans parasite has completely disappeared, whichever is the longer.

In the event that the “conflict†of disease, is between C.irritans (by far the most common of the 2 parasites), and a bacterial infection, with signs of bloody lesions etc, on the sides or elsewhere on the fish, act as follows:- I always recommend to first treat for the parasite, and when this is completed, to remove the “No-Ick†in the manner described above, then treat with “Revive†for the infection.

“Revive†is effective against not only Amyloodinium but also is an excellent antibacterial agent for gram negative bacteria, which are the causative organisms for the majority of those bacterial infections which we find in the aquarium. It also is very effective against many gill flukes as well.

Question 3).Should I use my UV lamp during treatment, and can I continue to add various additives?

Answer: Although we have had examples from several Hobbyists, where they have used their UV lamp without problems during treatment with “No-Ick†, there is in the literature some evidence, that there can be an unfavourable interaction between the rays of the lamp, and the active ingredients. Therefore we have warned against their simultaneous use which have caused no problem, but it safer to err on the side of caution. I would also point out, that UV lamps will have no effect whatsoever, on killing the parasites, so I really see no reason to feel worried about turning off the lamp for a couple of weeks. The lamp should also not be used if treating with “Revive†as one of the ingredients in “Revive†is very light sensitive.
As for the use of additives, such as trace elements, Kalkwasser etc, there is no reason at all not to continue with these, and in both our experience, as well as the hundreds of Hobbyists that have reported to us, have we had a single case of negative interactions.

(CONT)

 

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Part-11 (cont)

Question 4). Do you recommend, using “Noâ€Ick†periodically as a prophylactic treatment in my show aquarium, and if so how often?

Answer: Obviously prevention is better than cure. However I do not believe that once things are stable in the main show aquarium, that one should add our medication (or any other) as a preventative.

What I do advocate, is that every new purchase, of fish, or Invertebrates, or Live Rock etc, should be held in a small filtered quarantine tank for at least 2 weeks before being introduced to the main aquarium. This is the right place and time, to use the treatment, even if there are no signs of disease. If this regimen is followed then it is improbable that outbreaks of either parasite or bacteria will break out to cause you aggravation, losses and heartbreak.

Remember, when introducing new fish to an established tank, to do so in VERY subdued lighting, preferably in the evening. Do this as close to total darkness as you can manage. Leave off the lights for some 12 hours, and if practical move some rocks or other decorations, so that the existing inhabitants will pay more attention to searching out their favorite spot in the tank, and far less to the new arrivals. This greatly reduces stress, and the potential that this can cause an outbreak of disease.

It is important to be aware, that the C.irritans parasite has the capability to lie dormant for very long periods of time, below the epithelial layer (under the skin). It cannot be eliminated in this stage, by any treatment that we are aware of. However it also will seldom break out and cause a problem unless stress in the form of an intruder, as just mentioned, or adverse water chemistry causes it to feel it should seek a new host. By minimizing the chances of stress, one can protect your fish, from these infections to some degree at least.

Finally I would like to refer to the percentage of hobbist, who fail either with our, or other treatments. They are understandably upset when this occurs, and would like to know why.

In a large percentage of these failures we have been able to determine the likely reasons. There are still about 10-15% of such cases, where we are unable at this time to say with confidence that we know what is the reason. However for the vast majority of failures we can offer below, some guidelines as to the cause. ( failures amount to about 25% of total attempted treatments, so that 10-15% of these is only some 4-5%, of all outbreaks that we cannot explain)

Here are what we have ascertained as the major causes of “failed†treatments.

a) A wrong diagnosis has been made. As everyone will realize, Aspirin will not cure a broken leg. Thus if you do not make the correct diagnosis, and use the wrong treatment, not only will you not effect a cure, but as any chemical can cause some stress, you will often make the problem worse.

b) Treatment has been instituted, but the protein skimmer, and/or charcoal filtration has been continued. Depending on the efficacy of the skimmer and the amount and quality of the charcoal, much of the active ingredients of the treatment will be removed, thus ensuring a negative result.

c) Many aquarists are unsure about the amount of water in their tank, and often forget to include the water in their sump etc. Also they sometimes do not allow for the water displaced by large amounts oflive rock etc. Too little or too much medication, can have an negative effect. Too little will enable the parasite to continue it’s life cycle. Too much can have the effect of causing severe adverse effects in the fish. Before beginning treatment, it is most essential to calculate & then recheck the amount of water you are treating.

d) The fish are in an advanced stage of infection, before treatment is begun. As you will all be aware, if we are ill, the quicker we get to a professional, and begin the correct treatment, the better our chances of a complete recovery. When one leaves the treatment too late, then it is very hard to bring back fish, that are already at death’s door.

These reasons account for by far the majority of failures in treatment. Pay careful attention to them, as well as the points above, and your success, as well as your level of expertise will move into a high percentile. The satisfaction, not to mention the good feeling of saving your fish, and thus not losing money, will add enormously to your self confidence, and no doubt many fellow Hobbyists will seek you out to advise them also.

END OF FISH DISEASE ARTICLE.

Posted and edited for the saltwater hobby
by JHNRB