So I've done my research and bought an NTT Datnoid last week and I know they can be unstable. But yesterday it looked like he was suddenly on his last legs and having some serious swim blatter issues (swimming upside down and to the side, etc.). But today his color came back and he doesn't look like he's having any trouble swimming anymore, just acting normal. All I did was a water change between then. Nothing in the tank is really picking on him(just plecos, Bala sharks, and chocolate cichlids mainly) so I don't think that's the problem. Do they just not like busy tanks? Also if anyone can have any advice getting them to eat. Is it just a waiting game? Right now he doesn't look skinny or have any sort of sunken belly but still... Any input would be greatly appreciated.