Your tank is probably a bit small for a "classic" sea star - I suspect that a sandsifter would have your sandbed emptied of all living things in a couple of weeks or less - and then starve, as they often do.
A brittle star or a serpent star (just not one of the big green ones!) could work well for you though.
~Bruce
A brittle star or a serpent star (just not one of the big green ones!) could work well for you though.
~Bruce