Originally Posted by
jeep
"Parasites"... But do we know which kind? At this point it could be as simple as hex and treated with heat and metro for 10-14 days in water. Metro with food is great if the fish will eat it. Hex isn't contagious, they all have it. It's when a fish becomes stressed or sick that hex takes over a weakened immune system.
Like I said earlier, 93 heat alone will cure many fish and along with metro should be good. Keep in mind that isolating in a hospital tank alone can be stressful, and 93 heat and metro will do no harm to the other fish. Just do it slowly and make sure they have plenty of air. 2TBS salt per 10g will help them deal with heat and low o2 levels...