Fin issue -- what is it and treatment?

[robbokj]

Hi, all... long time lurker, first time poster.

Anyone have an idea of what this is (on the tail fin) of this purple tang? Looks like part of the fin is missing and the part where it's missing is a little red. Bacterial infection? Suggested treatment? Fish is otherwise looking/acting healthy and has been stable in this tank for 3-4 years.

Thanks--
Rob

 

[Barracuda1]

are you sure he didnt just cut himself? Because if not he may have fin rot

 

[JHemdal]

Rob,

I can't see the large missing section of fin well enough to hazard a guess - how long has it been like that? I would not run out and try an antibiotic treatment just yet, unless the redness gets worse, or unless the lesion is rapidly getting larger.

I'm also looking at the tiny scalloped marks on the trailing edge of its caudal fin. Could something in the tank be tagging it? I only know of two things that can cause that sort of fin damage in Zebrasoma tangs - aggression from a tankmate, or the atypical head and lateral line erosion they sometimes get - where fin erosion is the main issue.

Jay