Mantis?

[ed99]

I suspect I may have a mantis shrimp in my tank. The tank is relatively new (about 3 months now) and I bought about 150 lbs of new live Jakarta rock when I set it up. I have already removed one mantis that was walking across the top of the rock so he was easy. Earlier this week I heard three sharp click like a marble hitting glass. I have only heard this once. The other evidence is that I bought two new cleaners a week ago who I thought were goners immediately. Since then I have found them, but they never leave their hiding spot in the bottom corner of the tank. Cleaners I have had in the past were not that shy. I don't have any snails or crabs so I have not seen a trail of destruction.

Any thoughts? I have not seen any other sign of him day or night.

Thanks,

Ed