Be crareful, plecs create a lot of waste and put a lot of extra pressure on your bio-filtration that other fish of a similar size might not. For that reason I would never put a (smaller breed of, obviously) plec in anything less than a 30gallon. I don't even keep plecs that get bigger than 5"tear-scar said:cool, think I have enough room in the 20 gal to add it . . .