Asterina star. A decent part of the cuc, but they can get out of hand. Some will even bother your corals. They got pretty bad in my 125. I manually removed hundreds, and finally added a harlequin shrimp. He keeps them in check and looks amazing. Only thing is that if the shrimp runs out of starfish, it will starve. Not too much of a problem in my tank. I think they reproduce as fast as the shrimp can eat them.