It's a 48x18x20 75 gallon. I'm not to worried about the convicts as they are mainly for an added entertainment factor (breeding, fighting off the jag as a pair) while the jag is growing. I mean lets face it. 75 gallons of water and 5 inches of fish is only so much fun. What is amazing is that another jag in the 55 gallon directly on side of it, at no bigger than three inches is a constantly trying to get at any fish that gets on the right side of the 75 gallon. He is going to be a total nutcase.