My betta, Errie, lives in a divided 10gallon set up (divided three ways) with another betta, Snowy, a swordtail, a neon tetra, and a couple of fry that are being put into another tank in December.
Since Friday he has literally been laying around the tank -- laying on his pirate ship, in his barrels, on his betta hammock, on his moss ball -- you name it, he's laid on it at this point. The ammonia was high, so I did an emergency 50% water change and treated the entire 10 gallons worth of water with Prime, which got my ammonia (nitrites and nitrates were not high, but they are 0 now) to 0.25 ppm. It's still too high, but now I have to treat the tank of ich (showed up today on Errie and the neon tetra) also so I can't do another 25% tomorrow to get rid of that last bit like I wanted to. I'm using the API ich treatment to treat the ich, and I upped the tank temperature to 82 degrees (formally 78 degrees) because it will expedite the treatment of ich.
I don't know what is wrong with Errie though. He had no swim bladder issues. He has no fin problems. This happened so suddenly and he is the only one acting sick. He's normally energetic and swimming around his part of the tank. He's such an active, happy betta and loves to "play" in his ornaments (not flashing -- like rubbing against them -- he just likes to swim in and out of them). He also hasn't eaten since Saturday. I got him to eat two pellets Friday. Does anyone know what could be wrong with him?