They are really hardy fish that eat inverts, crustaceans, and possibly other smaller fishes. They are a lot like lions, being able to train them to eat frozen foods. They can get almost 2 feet though and at full size a 180g tank is the recommended size. Also, like lions you shouldn't try and handle them or net them without caution. They aren't poisonous, but they have armor like scales, are extremely strong, and have hooks near their gills that get easily caught in nets. Great fish to keep though, my neighbor has one and he says it cleans uneaten food from the bottom of his tank better than any crab could. :happyfish