What is this in the fish's body?

[arvin]

Can someone help me identify what this thing is?

 

[Fish Brain]

Looks like a lesion and bruising. Are there any other tangs in the tank?

 

[arvin]

yes. a same size yellow tang and a xtra large hippo. is this sign of aggression?

 

[Fish Brain]

How long have you had the fish?

 

[arvin]

for almost 2+ years

 

[downbeach]

You might check here:

http://www.chucksaddiction.com/disease.html

 

[arvin]

Thanks. It looks like it is healing. I don't see the dark/grey spot anymore. He continues to be active.

thanks for the link. very helpful.