I have a black brittle star with white bands on his legs that's about the same size. I just recently removed him from the tank and put him in the refugium because he's eaten 2 ghost shrimp and three cleaner shrimp (you know the expensive ones?). I finally caught him in the act so I was able to confirm it was him when he had his latest victim which was my mandarin, sadly we were not able to save it either. Use this guy with caution.