i am pretty new to the hobby(addiction) and am afraid that i may have a mantis shrimp in my tank. i occasionaly hear tapping in the tank like a coin tapping on glass, it usually happens in twos or threes, and today i found the front end of a dead hermit. all i have in the tank is snails, hermits, a watchman gobie, two clowns, a peppermint shrimp, a coral banded shrimp and two emerald crabs. one emerald has become quite secretive while the larger one is still bold.the coral banded is also quite secretive. i have not seen a mantis but have to wonder.