Originally Posted by jkdubs2
So I have been treating him with some meds in an iso tank. He doesn't seem to be getting any better or worse. Could these simply be tumors or cancer? The petco I got these guys from said they had got some rainbow fish in at the same time that all had a weird fungus on them and it got passed to other fish. Idk if that helps narrow what it is down or not.
Medications generally stress fish. I'd never use them. What you can do is add a little standard aquarium salt to your water change water. A little more than a teaspoon for every 5 gallons should be enough and run the new water a little warmer than the water in the tank. Change half the tank water every few days for two to three weeks and see how your fish does.
The combination of the aquarium salt, a lot of pure, treated tap water and a little warmth should help.