I have a 180 Gallon Reef Tank. I continue to add Blue Leg Hermit Crabs and can never find any after a couple days. Not even shells for those who say they molt. The entire crab is gone !! I had a Brtitle Star and removed and added 50 and all gone. Is it Possible a very Large Chevon Tang or Lieutenant Tang ate the entire crab. I have have seen both both Tangs bother them but not actually eat them . I don't know where else they could go ?