The Harlequin Bass is extremely hardy, and make a great starter fish for beginners. A 30 gallon or larger aquarium with abundant hiding places provides a good environment. As the Harlequin Bass matures and grows, it may prey on any smaller fish or small crustacean tank mates. Although these fishes can boss around some smaller tank mates, they are not normally overly aggressive to different species. They do not get along with other Dwarf Sea Basses or even bottom dwelling fishes that occupy the same territory, so keep a close eye on them when mixing similar fishes or ones that occupy the same territory. I would recommend only one Harlequin Bass per tank , unless they are a mated pair. The Harlequin Bass requires a diet consisting of a variety of chopped live meaty items and frozen prepared foods.