My dad has a purple lobster in his 55 gal. and it's pretty good most of the time. You just gotta make sure you feed it, or it will find something (fish) to eat itself. I think they are a beautiful addition to any tank, but it depends on which one you get. You could get one that comes out a lot in the day and night, or you could get one that runs into its little hole every time someone walks up to the tank.