Yea I'd say between 55-75gal minimum, depending on additional stock. They get a little hefty and because they can get aggressive, it's best to give them space. They aren't a "hard" species to keep, but as reef said, they have their sensitivities, so try and do some homework before you buy, and keep in mind that if you're adding to a community tank, you need to make certain that it will tolerate current parameters and temps, or that likewise, if those are changed to meet its needs, that the other inhabitants can tolerate those changes. They like pretty warm waters in the high 70's to about 80, and are carnivorous, so keep that in mind if you've got little fishes and inverts cruisin around safely now, lol. I dont know what you have in there now, but little one's like Blennies, Damsels, Clowns, Dragonets, etc. would be a yummy snack once it reached adulthood. If you do get it though, make sure to take pix and keep us updated!