Black/Brown Marks on Atlantic Blue Tang

[TheMillennialReefer]

Ok I have no idea what’s going on with my Atlantic Blue tang. He’s been in the tank for a week after QT and initially I thought it was bruising from initial fish aggression but some days it looks better but some days it looks worse... I was finally able to get a someone decent picture. I have no idea what’s wrong

 

[TheMillennialReefer]

Also haven’t been able to catch...

 

[halfmoon61]

If he is otherwise healthy could be turning into adult colors?

 

[TheMillennialReefer]

If he is otherwise healthy could be turning into adult colors?

His adult should be blue. It’s like a brown color. But maybe?

He’s definitely the most skittish in the tank for sure. So I don’t know if it’s an infection or what. No spots or anything.

 

[Jay Hemdal Verified Community Expert]

His adult should be blue. It’s like a brown color. But maybe?

He’s definitely the most skittish in the tank for sure. So I don’t know if it’s an infection or what. No spots or anything.

Best case scenario is that it is changing to adult coloration (they really aren't very bright blue in captivity) - however, the color change really wouldn't be blotchy like that, they just sort of pale out and start to turn very light blue.

You mentioned aggression what fish were picking on it? Any damage to its caudal fin? Is the fish feeding normally?

Jay