Yellow Tang Dorsal Fin Damage

[Julio Hernandez]

Howdy!

This is my first time posting and I need some help identifying what is wrong with my yellow tang. I recently noticed that my yellow tang had some damage on his dorsal fin near his head. I believe its a bruise but I'm not sure. The tang started getting aggressive with a copper band that I introduced about a month ago. It would hit the copper band with its tail and the copper band would move sideways to protect its self with its spikes. After a couple of days of minor aggression, they started getting along. Recently I have noticed it tries to scratch the area on the rocks. The tang eats and swims around like normal. I feed him frozen brine, omega one marine pellets, omega one veg and also nori a couple of times a week. I attached some images below so y'all could take a look. I would appreciate any help. Thank you!

 

[Sashaka]

I'm not an expert, but I have treated many injured fish successfully. It's really hard to tell from the dark pictures how bad the injury is, but I would just watch the fish for awhile. If it's eating and there is no signs of infection, the fin will probably heal if the two fish are not fighting anymore. Keep your tank parameters good.

If it were me, I would setup a sick tank in the event the fish needs to be pulled and treated..or just needs a peaceful place to heal without bullying. Infection can take a fish out in a day to several weeks depending on the type of infection, so a low stress environment is helpful.
Good luck!