I just bought a few new zoa frags and some of them are doing great, but one frag only has one of nine polyps open. Scratch that. One of eight, because one polyp is gone. I have a red mythrax crab and he was hanging out on the rock with the zoas on it today. Can they/do they eat zoas? What are the odds the zoa polyp coincidentally fell off or died unrelated to the crab? I've only seen him mess with my candycane coral, and that's only because he accidentally grabs tissue when trying to clean the skeleton. He's also irritating my 2 new duncan frags, but i don't think he is actually eating them. This isn't the first time I've mysteriously lost corals, but I though I removed the offenders already, who were a large hermit crab and a king crab, both caught in the act. I'd love to seperate him until the new corals seem open and healthy just to be safe, but I can't catch him! My whole structure is glued/epoxied together so it would be very destructive to forcibly remove him.