Asterinidae - Asterinas Star Fish - This starfish eat coralline algae and some corals, specifically SPS and Zoas. Usually you'll see them with either missing legs or parts growing, even a small piece can grow in time to a large Starfish. Harlequin Shrimp are good at eating them but will also eat other type of Starfish, so you need to be careful when putting on in your tank. You can also pick them out.