Discoloration on tang dorsal fin

[mattcoug]

My mac tang developed an odd discoloration on his dorsal fin. It first appeared as a darkened circle that now has a large white circle surrounding it. There is nothing on the skin surface, but the white area appears to be slightly swollen.. something like an inflamed allergic reaction to a bee sting on a human. This is a fowler, no anemone to sting etc. just the rock.

Thanks in advance, thoughts?

 

[mattcoug]

I been feeding him nls hex shield, which is nls pellets with metro. Whatever it was has almost completely cleared up and I spect in a few more days I won't be able to tell anything ever happened.

Before i started the medicated food it got much worse than the pics appear, so either the metro killed something or the fish just had a "bruise" that took time to heal.
In any case, all's well that ends well.