I found my cory catfish laying in the corner of the tank this morning, dead. I have no clue why. I have about a five gallon tank with one other cory catfish, and a betta. I think that the betta might have killed him, but I don't know. He seemed perfectly healthy and active the day before. I came home two days ago from a weeklong trip and I had my little brother take care of my fish tank. I just got him two weeks ago, can someone please help me?