Is this an issue or disease on my Clown?

[Sammydog]

I'm not sure what this is, or if it is an issue (I really hope not), so I'm asking the question. Hopefully one of you can set my mind at ease, or send me down the right path.

Basically, I noticed a circle area on the side of my clown (on the bigger more aggressive of the four I have) and in the middle a few scales don't look right. I've not noticed this before and I do spend a lot of time staring into the tank.

For the reference of those who can help, the tank has four clowns, a bi-colour blenny, mandarin and four janitor crabs. On the coral front, a lot of mushroom, a decent sized frogspawn and an area of zoas.

I finally seem to be getting on top of a hair algae outbreak after 6 months, and will be devastated if this is a major issue.

Excuse the photo quality, I just wanted a shot of the problem area, not a great photo. Its only one of the four clowns with the marks.

 

[Sammydog]

My current water readings as well;

Gravity: 1023
Ph: 8.0
Ammonia: 0ppm
Nitrate: 5-10ppm
Nitrites: 0ppm

 

[ccCapt]

Looks like bite marks from fights with the other 3 clowns. Are these 4 clowns and mandarin in your 90 litre (23 gal) tank?

 

[wontonflip]

Is he acting normal (as normal as clowns get, that is)? If it's not raised, it might be an injury. Anyone been picking on him?

NINJA'D!

 

[Sammydog]

Is he acting normal (as normal as clowns get, that is)? If it's not raised, it might be an injury. Anyone been picking on him?

NINJA'D!

I haven't noticed any fighting lately. The marks don't look to be raised. Normally when they do fight I might find a nipped fin, but the pairs normally stay in their own bits of the tank.

Looks like bite marks from fights with the other 3 clowns. Are these 4 clowns and mandarin in your 90 litre (23 gal) tank?

That's exactly what my wife said. They have fought previously, but this fish had been the instigator.

Yep, those fish are all in the same tank.