I’ve got two discus for 4 months now. they were doing fine until a couple days ago, one of the fish got sick (not sure what kind of sickness). its skin color darkens, it hides a lot, and has what seems to be peeling skin on its body, possible fungus. I removed it into a hospital tank. it’s getting better but the color is still dark and now I noticed the eyes seems to be swollen. but it’s definitely NOT a popeye. what should I do?
It is definitely bacteria infections.
When the discus fish turns dark, it indicates that the fish not feeling well. If no action taken, then the fish will get sick.
Then the epidemic spreads, all the fish will die.
Apply anything that can kill parasite and bacteria.
Anything that is handy to you, like Acriflavine, Methylene blue, Malachite green, Formalin, potassium permanganate, salt and antibiotic.
Yes. Treat them in a hospital tank.