Mantis shrimp can deliver lethal blows to other crabs, shrimp and fish. A loud "click" in your aquarium might be an indication of a mantis shrimp attacking or scaring off other inhabitants. Rarely out in the open, they will stack little shells and rocks around their hiding spot. The 'X-Terminator' Mantis Shrimp Trap is here. Now you can catch those unwanted shrimps and crabs without disturbing the beauty and delicate balance of your aquarium.