I've have one for over 20 years now. It doesn't get anywhere as large as the Panther Grouper, which get pretty big. Like most grouper it's very aggressive in it's territory, which is the whole tank, and will try to eat any fish that it can. It will also be very protective of it's territory and will harass any fish that it feels is competition, to the point where the other fish will be shredded or possibly killed, especially if the fish isn't that aggressive. Otherwise it's pretty shy and will hang in the background, where you wouldn't see it that much.