What species of puffer? You never know if a puffer will be aggressive or not to it's tank mates. Even one who played nice as a juvie, could one day wipe out the entire tank when mature.Ajno;5015744; said:I was just at a fellow members house and he had a puffer cruising around his 300 gallon with clown loaches,koi,and cichlids. Pretty cool, he said if the puffer grows up around other fish it gets used to them. I want one, but know the biggest tank I could get would be a 200 gallon tank.