I have heard of it and yes they do live!! Mnay people put teddy bear crabs in their sump's because they dont want them to eat their hard corals. You get alot of crabs form the live rock you purchase at your lfs. I even knoe of a guy that comes into our store that got mad at his mineotis(sp) grouper and stuck him down there and he is still alive and kicking, i dont suggest doing it with fish but critters will live i believe... pls someone correect me if i am wrong.