Clown Fish Is Scratched

[Nate92483]

My clown fish has a really bad scratch down her side. I had her for a very long time and she was fine. I also have a yellow tang who is kind of territorial. They live in a 65 gallon 3ft tank. I was wondering what would cause this? I haven't seen the tang attack her at all. They seem to all get along. And my other question is what is the best way to treat this scratch?

 

[i cant think]

My clown fish has a really bad scratch down her side. I had her for a very long time and she was fine. I also have a yellow tang who is kind of territorial. They live in a 65 gallon 3ft tank. I was wondering what would cause this? I haven't seen the tang attack her at all. They seem to all get along. And my other question is what is the best way to treat this scratch?

To me that’s a slice from the tang, look at the marking shape and the tangs scalpel. Also tangs are known to draw blood even if you don’t see aggression they often do it during the time you aren’t looking at the tank (Lights out, when you’re sleeping/working ect..)
IME get the fish into a QT tank and treat with melafix, it should heal up naturally anyway!

 

[JumboShrimp]

I agree with @i cant think...

... looks as if your Surgeon Fish (Tang) performed some unwanted surgery on your Clown.