Goldfish with Black Smudge
A few weeks ago I posted a topic about a sick goldfish. I found trapped under the internal filter, helped him out and his dorsal fin was partially shredded. Not surprisingly, he developed a white, cotton-like growth on the affected fin (probably fungus). I treated him with Furazone Light for about a week after consulting the forum here and he is more active, eating, and swimming.
Everything seems fine with him except, he has a black smudge on the affected fin. (It hasn't completely grown back yet). Is this cause for concern, or merely the fish healing? Thanks for your help.