Hello, our male betta is not doing well at all. About a week ago we noticed he wasn't really eating much. Then after a few more days we noticed his swimming was a bit weird. He would float tail-first to the top and then swim back down. Now he is just on his side at the top of the tank. After we first noticed his odd behavior we changed his water, which did nothing.
Here are the specs:
He lives in a 3L container and we change the water frequently to keep it clean and always do a full water change. He has always reacted fine to this. We do not use a filtration system or any other mechanical device. No 02 stones or anything like that. We treat the water with a betta specific water treatment. Probably the main thing we have done wrong is over-feed him. He probably ate 10-12 micro pellets a day easy. He's been eating that way for about 10 months.