I have a 20 gal. tank and was wondering what kinds of starfish would be safe to put in it...I do have some small coral frags so I need something thats reef safe...would some sort of brittle star be alright? I received a chocolate chip star w/o knowing it was not reef safe and will also eat all of my snails...anybody have any suggestions on how to keep my choc. chip star in my tank but not allowing him to eat my corals...or snails?