Richard from TBS tossed in two of them with all the stuff he sent me. Shockingly, one of them is still alive.
They're filter feeders so they need good flow and lots of stuff floating around for them to feed on. They'll also move around on their own and settle wherever they choose. I feed Rod's Food because it has a bunch of stuff in it, and i've been alternating between PhytoFeast and E.S.V. Spray Dried Marine Phytoplankton every other day or so.
Good luck! :)