Can anyone help me out. I added a royal starfish (Astropecten spp.) to my tank about 2 weeks ago. All of the sudden about 3 days ago i noticed it looked like it had a bite taken out of it on one of its arms proximal to the central disc. The bite was about 1cm wide. It has gotten larger each day so now it is about 4-5 cm long. I have not noticed any of the fish nipping at it. Fish in the tank are a maroon clown, perc clown, fox face, and blonde naso tang. I am currently video taping and have about 3 hours of footage that I've reviewed without any fish nipping at it. I plan to tape overnight tonight so I may know more about that potential cause in the morning.
Does anyone know about any sort of starfish wasting type disease that could be causing this? See pix below.