I don't have hermit crabs anymore. When I bought my red grape algae from live aquaria a year or so ago. There was a devils hand coral attached to it. It was my first coral for that tank. It was doing well untill we added a hermit crab. The hermit crab kept sitting next to my DH coral and making it lean over. I would move the hermit crab far away from the coral and a few hours later the dang thing was back again. The hermit eventually killed my free coral. Never again will I have hermit crabs in any of my tanks. The only hermits I had was scarlet hermits.