Two weeks ago one of my male kerri tetras suffered too high of a dose of flubendazole (whoops) in quarantine and didn't take it very well (symptoms were lethargy and fin rot/nipping from his tank mates). I did frequent water changes, didn't observe signs of nematodes, and eventually moved him to the display tank after he started improving. He and his five other mates had been quarantined just shy of 6 weeks up until the flu treatment.
A week in the display tank and his fins were healing but he still wasn't schooling with the others. Then I noticed a small white spot on one gill, and fearing ich, immediately moved him into a 5 gallon isolation tank. There have been no signs of ich or other symptoms in the display tank yet.
He has now been in isolation for a week and still isn't doing well but I no longer think it's ich. Symptoms now include: minor lethargy, slight pop eye, and now most recently mouth rot and an open wound on the side of his face that I initially saw the spot on. His appetite is fine and he moves around well when engaged at the glass.
The mouth rot does does NOT include any fluffy or fungus-like growths. Rather, his lips are gray and look worn away. The lesion on one side of his face/gill has a slight pink tinge and looks like flaps are peeling away. That, or it looks like a combination of growth and lesion. It's hard for me to tell.
I was just going to see if he could recover on his own, but now with the worsening lesions I want to know what's wrong. Does this sound like a bacterial infection or something else? How would you treat it? So far I have been doing 50% water changes every day. Ammonia and nitrites are 0 in all tanks, nitrates are low.
Bad side (of course I can't get a clear pic of the side that counts :icon_roll):