was at the bottom of the tank, but still moving and otherwise seemed to be ok. So my sister and mom changed the the water and cleaned the tank. We did everything that we usually do, and the fish seemed to be getting better. Then about 15 minutes later, it was floating at the top. My sister thought it was dead and poked him and then he started swiming upside down and side ways. The temperature was a little higher than normal (we usually kept it at 73 and it was at 80) so we put cool water in and it was at 76. He's now dead. I looked it up and I thought it was a problem with its swiming bladder. But from what I read, I thought in a few days it would clear up on its own. Can a Swiming bladder problm kill in a few hours?