Black Molly - Mr Attitude = STRESS

[Black Molly]

I inherited a fish tank and a Molly and 3 Corys from a friend who died in January.  I got some more corys and later on some tetras for the Molly to have company. But he hates them. He bullies them and they bully him.  Now he has fungus on his mouth and fin. I need to not stress him oUt more. Should  I take him out and quarantine him or should I treat the whole tank? ... it’s a 29 gallon tank freshwater of course I keep it around 80° it’s planted but I’ve had trouble with the plants because I was keeping salt (due to Molly’s ICK problems earlier) in the water and I cycled that out.  The corycats  seem to be doing fine.  It’s  the Molly thats giving me a fit. Treated him And the whole tank with the three medication’s that are recommended on Aquarium co op ... probably about a month ago.  I turned the lights up a bit to help the plants and now he has fungus on his mouth and top fin. 

[Guppysnail]

I would personally remove to a QT tank to treat and to lower stress interaction for both him and the other fishes. 

Welcome to the forum. 

[PineSong]

Welcome! It is kind of you to take on the care of your friend’s fish. I struggled with my first mollies, too. I also you move the sick fish to a QT tank if at all possible and treat the fungus while focusing on excellent water quality. I believe Maracyn is the recommended antibiotic but you may want to verify with a post in the “Disease” section of the forum. I wish you and Mr. Attitude good luck!