yea i was worried about the puffer with other fish.... and suprisingly..... my blue gaourri (sp) which is sopose to be really tame.... picked on all the other fish, and the puffer just sits by himself in the corner, he likes eating the earthworms that i put in there before the stingray can get to them, but once again... the ray is in a 55 right now while my 300 is filtering out...im putting some rosyreds in the tank tommorow as a starter fish then in a week im gonna move the ray in there. And before i get my head bitten off.... my lfs wouldnt hold on to him for another two weeks before my tank was ready so i am doing water changes every other day in the 55