A friend is battling an outbreak of what he/they think is Chilodonella. Discus Owner has researched symptoms and various parasites and thinks he has narrowed it down to Chilodonella. I have an old "Scope", but no cover slips at present, to do a scraping and try to positively I.D. the culprit. So, we're still guessing at this point in time.

Presently, DiscusO is treating with an over-the-counter medication that is largely anti-fungal (Malachite Green and Formalin), and doing nightly water changes. He has already lost one big discus in the 125 gallon "mixed" tank (a couple plecos, clown loaches, and Angels). As Chilodonella is a protozoa, shouldn't he be using an anti-protozoan drug to target the parasite? Several anti-protozoan meds come to mind for me, but ..thankfully...I have zero experience using any of these types of products in aquariums/with fish.

Will using formalin screw up the good bacteria in the tank? Any suggestions for an effective anti-protozoal med, or other type of medication?

DiscusO is frustrated and afraid he will lose about $500 worth of gorgeous discus.

Help?