We have a star fish Pauciforis who's leg is slowly dying it started 2 weeks ago looked like a bite out of leg then the end of leg was gone and is slowly getting shorter he is moving around the tank Don't know what to do. We have had him for about 8 months in a 125 gallon tank with a Strip Wrasp, a Yellow Tang and snails and blue crabs and red crabs,coral banded cleaner shrimp and another star fish orange??? came with tank we have had a year any suggestions?????