Need ID help please. I've been hearing this snapping noise like a mantis shrimp in my tank for months now. There was one big mantis shrimp but I was able to catch him but the snapping noise at night continued. I was also losing every hermit crab and snail I put in the tank. This thing also ate my blue tangs tail and some other small fish I had in there. Last night I set a trap using a cut up water bottle and baited it with some hermit crabs. I noticed this morning I caught this weird crab thing. Could this be the snapping culprit? Do crabs make popping or snapping sounds like mantis or pistol shrimps? If so what kind of crab is it? Thanks.