Hmm, it is a little small which might be your issue. But do you have a plan when he gets to be like 3 feet?Reason why I keep him in a 75 gallon with my other fish is because my 150 is full of mean fish. I got an Jardani arowona and two oscars and one Jack Dempsey and one black belt and a convict and a Bichir and a red devil their not that big yet but still their a mean bunch.