Fish with a black spot and black on edge of fin

[ATTIE]

My fish were put in stock tanks while the pond was being redone. I happened to test the water and found out the PH and Ammonia etc. were all off the charts- so I know the water wasn't clean. Anyhow, when putting them back, I noticed one had a black lesion looking spot on it, and its fins had some blackening around the edges. I know this wasn't there before, it happened in the time it was in the dirty stock tank.
I'll try to post a photo but it isn't a very good one. I don't think I got one of the lesion on its side, but you can sort of see the fin issue. Thanks! T

 

[bettasngoldfish]

The black coloring can be a sign of healing from a burn which could have been caused by an ammonia spike.

As long as your fish is acting fine otherwise I would just keep a close eye on water parameters.

 

[sissy]

could also be color change .My fish have little spots of black here and there and have had the spots for years now