we bought my doughter her first aquarium for Xmas. It is a five gallon tank. it has a filter heater and a five gallon rated bubbler. We started with just a dwarf gourami and after the first week all was well so we got a small catfish. they have been fine untill now the gourami in having trouble staying upright. he is proping himself aginst things in the tank to try and stay upright. Every once and a while he spaztically swims to the surrface and darts around the tank. I hope i have givin enough info. if anyone can help i would realy appreciate it.