The crazy horseshoe crab

That is brutal. I could never let an animal suffer like that. Obviously they are not open water swimmers and what it's doing is not normal.
 
Actually as juveniles, they are partly open water swimmers. Horseshoe crabs are capable of swimming just as it looks in the video to get away from predators, or change locations in their search for food. They swim upside down and move with the currents. In aquariums, there is significantly less current than you would find in the ocean, therefore they appear to just bob around the water column. Juvenile horseshoe crabs in calm waters in nature will float upside down at the waters surface and eat the things that float on the surface. As they get older, they swim less and less and eventually give it up pretty much altogether as adults, sticking mainly to the sandbed.


Keep in mind that while they do like to swim, they are not a strong creature and will get stuck on powerhead intakes and not be able to pull themselves away. Turning off the powerhead or a gentle push away from it will allow it to free itself.
 
Care to back all that up with some published articles? You seem to want to disagree with everything I post about these crabs...even when I post an article to back my statements. Every article I read says they bury themselves in the sand during the day and forage the sand for food at night. I never saw anything about them being open water swimmers....but I'm sure you can provide that in a published article. ;)
 
Care to back all that up with some published articles? You seem to want to disagree with everything I post about these crabs...even when I post an article to back my statements. Every article I read says they bury themselves in the sand during the day and forage the sand for food at night. I never saw anything about them being open water swimmers....but I'm sure you can provide that in a published article. ;)

I don't know anything about horseshoe crabs, but I can say that anytime I've ever seen anything swim upside down there was something wrong with them. Is it possible that the flow is so strong in the tank that it literally picks him up off the sandbed? At that point he's basically a kite with legs. I've gotta agree with CCapt.
 
:fechten2:

Let's see those articles! I have Horseshoe Crabs and on occasion they have done the same thing. Normal? When one of mine did it I thought he was dying or something, but maybe swimming like that on occasion is somewhat normal. :dunno: I would like to know for sure. Anyone know?
 
I don't know much about them at all... They aren't very commonly kept in the hobby since it is pretty well known that they require a larger habitat than most of us can provide.
 
"It takes 9-12 years for a Horseshoe Crab to reach maturity, so all the Horseshoe Crabs you see on the beach are at least 9 years old and have a life span of 16-
40 years. The Crabs grow by molting or shedding and emerge 25 % larger with each molt. Molting occurs several time during the first two to three years and about once a year there after. After 16 molts (usually between 9 and 12 years) they will be fully grown adults."

Posted for my previous response in how slow these things grow. Taken from "http://www.thomaspointbeach.com/horseshoe.crab.fun.facts.pdf"

"The Horseshoe Crab can swim upside down in the
ocean." From the same page.

"On the underside of the opisthosoma is a series of six page-like structures called book gills. These are versatile organs used not only to breathe, just as fish use their gills for respiration, but are also used for swimming. Horseshoe crabs swim upside down by flapping the gills like wings. Swimming is an alternative mode of transportation used in emergencies, mainly to escape from predators or if the animal finds itself in rough surf."

From Daily Kos: Marine Life Series: Horseshoe Crab Anatomy Article referring mainly to adult crabs.

They also swim ashore to mate.

From Uncensored WildEyed: Horseshoe Crabs Mating! Nature Calendar


https://kb.osu.edu/dspace/bitstream/1811/5558/1/V70N05_276.pdf
^An academic article relating to the swimming habits of horseshoe crabs.

" They’re frequently offered in the trade and extremely hardy, given the proper care and system. Life span is 16 – 20 years in the wild, but unfortunately, many are inadequately housed in captivity (especially in reef tanks) where they quickly deplete the sandbed of edible fauna and slowly starve to death over a period of 6 to 12 months."

WWM simply backing up what I said in an earlier post in that they EAT like crazy and will need supplemental feeding the same as creatures like sand sifting stars.

"In the wild, the young stick to the shallows and intertidal zone."

"They also have a tendency to occasionally swim around upside-down – also normal so no worries."


WWM does say that they need tanks of several hundred gallons as adults. And I fully agree. However as babies as they're frequently sold in the hobby, it takes so long for them to outgrow a relatively normal sized tank, that it's not unheard of to keep juvenile crabs and rehome them when they get too big.

Also noting that WWM also states that they enjoy cooler waters so you if you run your tank on the upper end of the ideal reef temperature scale, you will decrease the lifespan of the crab.


Like any other creature, it requires proper research into diet and habitat requirements and will need rehoming when it gets older, but keeping a horseshoe for 2-3 years in a 55g aquarium (which is what my tank size is now) is not unheard of nor is it detrimental to the crab provided you pay attention to what it needs. Just because it requires special care doesn't mean it's completely unsuitable for the home aquarium.


Edit: I hope I'm not coming across as snarky or anything, I just disagree. I spent 3 months in college studying horseshoe crabs as part of a field assignment/project/internship. I just think they're an incredibly interesting animal that is virtually the same as they were in prehistory. They haven't evolved hardly at all in eons and yet they're full of personality, quirky, and were really fun to study. I bounced around from major to major and did so many different projects like these at university that while on the larger scale, I might not have a lot of broad spectrum knowledge, I do have a few deep pockets of information on specific things that actually do come in handy.
 
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Awesome! All that just enforced what I said.

Swimming is an alternative mode of transportation used in emergencies, mainly to escape from predators or if the animal finds itself in rough surf.
I didn't see any predators in his tank or ruff surf. In fact, the way it was flipping around it looked like a fishing lure. Good way to attract predators.

They’re frequently offered in the trade and extremely hardy, given the proper care and system. Life span is 16 – 20 years in the wild, but unfortunately, many are inadequately housed in captivity (especially in reef tanks) where they quickly deplete the sandbed of edible fauna and slowly starve to death over a period of 6 to 12 months.
Yep...I posted that too.

It requires proper research into diet and habitat requirements and will need rehoming when it gets older, but keeping a horseshoe for 2-3 years in a 55g aquarium (which is what my tank size is now) is not unheard of nor is it detrimental to the crab provided you pay attention to what it needs.
How many times has it molted in your 55g tank in the 2-3 yrs you have had it? And where do you plan on rehoming it?

Again, all you posted just enforces that this is a creature best left in the ocean.
 
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I did not post that video to start a kerfluffle. The horseshoe crab spent the first several days scooting himself along the bottom of my tank, digging into the sand, climbing on my rock, basically looking like he was exploring his new home. I did not rashly buy the crab because he was cute and different. I saw him in the LFS, went home, did some research and determined that I have enough open sand bed for him to live happily for a while at least. I took him home with the understanding from my LFS that I could bring him back when 1) he grew too big or 2) when I felt that he had cleaned my sand of anything nutritional for him. I have a 75 gallon tank, granted not as large as some, but my rock is situated at the back of my tank, leaving the front half of the tank open. The crab has been very active, this was the first time I had seen him do something of this nature. If you notice in the video, he moves along the bottom at one point and then gets himself back up into the flow from the powerheads again. The flow from my powerheads has not affected his movement on the sand before and nothing has changed in my tank. Except perhaps my enjoyment of my crab's daily activties.

I am new to reefing, however, I do not go lightly into something new. I did research, I talked with people I know that have saltwater tanks, I made sure I had at least some of the basics before even beginning to look for a tank. I have found a great deal of information here and any number of people willing to answer questions, which is greatly appreciated.

Having said all of that, if the moderators feel that removing this thread will help keep the peace of the board, then please do so.
 
I had a friend that had a horseshoe crab he trained him to come to the surface of the tank and eat a piece of krill from him. Make sure your rocks are on the bottom of your tank (not just sitting on the sand) they can get under the rocks and cause an avalanche which will most likely smash them as well as possibly breaking your tank.

Good luck with the little man :)



I did not post that video to start a kerfluffle. The horseshoe crab spent the first several days scooting himself along the bottom of my tank, digging into the sand, climbing on my rock, basically looking like he was exploring his new home. I did not rashly buy the crab because he was cute and different. I saw him in the LFS, went home, did some research and determined that I have enough open sand bed for him to live happily for a while at least. I took him home with the understanding from my LFS that I could bring him back when 1) he grew too big or 2) when I felt that he had cleaned my sand of anything nutritional for him. I have a 75 gallon tank, granted not as large as some, but my rock is situated at the back of my tank, leaving the front half of the tank open. The crab has been very active, this was the first time I had seen him do something of this nature. If you notice in the video, he moves along the bottom at one point and then gets himself back up into the flow from the powerheads again. The flow from my powerheads has not affected his movement on the sand before and nothing has changed in my tank. Except perhaps my enjoyment of my crab's daily activties.

I am new to reefing, however, I do not go lightly into something new. I did research, I talked with people I know that have saltwater tanks, I made sure I had at least some of the basics before even beginning to look for a tank. I have found a great deal of information here and any number of people willing to answer questions, which is greatly appreciated.

Having said all of that, if the moderators feel that removing this thread will help keep the peace of the board, then please do so.
 
I do have my rock on the bottom with the sand around them. Something I learned on these very forums! I have noticed that when I am in front of the tank, he will follow me back and forth somewhat. My fish tend to do the same. At first I figured it was just because they wanted food, but they do it even when I have just fed them. I figure they are either greedy, or they are nosy/curious.
 
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