I have an explosion of asterina stars. Historically they have come and gone, but now they are out of control. I have found that the largest ones are eating my pink zipper Zoas. I have lots of other zoas, but they are only ever on this one colony. I know harlequin shrimps will take care of the problem, but I have 3 other starfish in the tank, a tile fromia, blue linkia and a brittle star. Any one have any other suggestions?