I am working on removing my 3rd Mantis shrimp from my reef tank. The first one was quite large and really bold. He would swim out in plain sight during the day. I would lose things here and there...(fish, shrimp, snails, crabs, etc.) The second was in a small piece of live rock that I put in my refugium and was easy to capture once I heard his clicking. The 3rd, however, I havn't seen...I only hear the clicking. All I can say is get rid of him before he gets too large! He will wreak havoc.