My take on starfish is a "better left in the sea" approach as most ( but not all) don't survive in captivity to long, maybe 12-18 months at best. Anything that multiples fast I remove, as I don't want these things to use up valued space, but that's just my take. Some are predatory, some can pop a clam with easy, some annoy corals, and some do a great job of mixing sand....