dark spot on firefish..

[doox00]

I have 3 new firefish in QT (had em just over a week) they are doing great, I have been slowly lowering the salt down over the past week to get to hyposalinity state (its at 1.015 as of right now).

One fish has a few dark spots on him, only the one side, has had it since we got em.. it almost looks like its his insides, but the others are not like this.. not sure if you can tell but here is a photo I just took. This anything to be concerned about?

 

[Sk8r]

That's odd. I've had firefish for years and not seen that. They have an odd fine-scaled skin. It might be a scrape or bite.