Hi everybody- a friend of mine called me in a frantic this morning, saying two days ago his yellow discus died. and today, Biscus the discus died. Yellow guy had a weird cotton ball thing on his face (pic below) Biscus just up and died. He's got more discus in that tank. Due to the price and emotional attachment we're doing everything we can to save them. Unfortunately, I had to admit I didn't know everything about everything, and I'm turning to you guys for help. Theres also a fire eel in the tank, so we have to play safe with the medicine with that one in there. I believe theres a cray fish or two as well. He says his water params are fine, discus friendly. Low pH 0ppm on ammonia and nitrites. Also 0 ppm on nitrAtes. which is a tad concerning to me. Could just be me though. When cotton ball face happened, he put Pimafix in the tank. Supposedly safe for everything and everybody. But does anybody have any ideas? he's in a rough spot and losing his discus isn't helping. Thanks always.