he is a beast in my tank but not being overly aggressive towards my other fish. he was laying on his side in the 30 gal. rubbermaid tub that i put him in while i was dealing with my pond. i thought he was severly depressed so i introduced him to his new tank, he laid on the bottom for all of 2 minutes and then started cruising around like he was hot ****. now he looks like he was raised in my 55 hes so comfortable. feeding time so now ill find out just how comfortable he is.