The frontosa is only about 8", and does pretty fine. Frontosa are slow moving fish who prodominantly hang out on the bottom in a cave. My frontosa comes out to eat and swims about only occassionaly. There is actualy plenty of room. I have alot of rock in there and there is still plenty of room to move. Check out the attached pictures, you will be surprised that there is so much room to move. There are also plenty of places to hide. The frontosa is about 8 " long, and so is the Tangerine Tiger; however, my tank is 16" wide(deep).