I HAVE A 5 GALLON TANK WITH 1 BLACK TAILED PLATY AND GREEN CORY CATFISH AND A BETTA. my Betta spends all his time under a dercoration i bought and my platy mostly spends his time at the top being active and my catfish at the bottom .Comet goldfish and betta are about the same size will they all live together in a 5 gallon tank? and will any of the fish be killing each other because my Catfish killed the other platy(red wag platy)