Hi everyone, I'm looking for some advice to see if I can save my favorite angelfish, Johnny. I have had him two years now. He was continually staying at the surface, not exactly gasping, but keeping his mouth right up there. No other fish were doing it, but I checked water quality first (ammonia 0, nitrite 0, nitrates were a little over 20ppm, so i did a few PWC to bring that down). He continued hovering at the surface, then he began alternating between hovering and laying on the bottom in the plants. Yesterday when he was lying at the bottom I noticed his coloring looked funny on his underside, almost brownish patches, maybe reddish? Its hard to tell as he's a black marble. I thought maybe he was injured by the other angel in the tank. Then when he went up to the surface I noticed white stringy poop coming out of him. I removed him to QT. Now he is in QT and lying on his side on the bottom. he will get up and swim if i disturb him but otherwise he's lying flat. I'm looking for any advice for what I can try to treat him with, or if he is too far gone (i hope not!) tank info: 60 gallon heavily planted fluval 406 aqua clear 50 small powerhead airstone 2 male angels 3 yoyo loaches 5 black molly 1 bristlenose pleco (juvenile, very small) ammonia: 0 nitrite: 0 nitrate: 10ppm ph: 7.4 Any advice would be appreciated, he's my favorite fish and I'm so bummed.