The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
The one I hear about most is ich. That's a parasite.
Then swim bladder disease which supposedly isn't a disease at all.
Popeye, fin rot, annd there's ammonia and nitrite poisoning.
Those are the ones I've heard of.