So I have known for a while now that emerald crabs were only partially reef safe and I have had two fairly large emerald crabs in my tank for around a year now and they had been model citizens or so I thought. Tonight a little before my lights went off I noticed one near a frag of clove polyps so I decided to watch him. While I watched him he proceeded to rip of one polyp and eat it. I was able to catch him and banish him to my sump so I guess I need to go crab hunting for the other one. I'm glad that he only ate the clove polyps, as far as I know at least.