I am sorry.. But I am a firm believer that even though these fish can be kept freshwater as juvenile, they should be in saltwater. Ever heard of a Green Spotted Puffer? Ever seen a full grown one(6-8")? Yeah.. My point exactly.
Also, any fish that grows larger then a small automobile, should not even be offered to home aquaria. I could get Arapaima Gigas and RTCs, but I don't want to offer them. It's not right..