I have a 75 gallon saltwater aquarium. I have had it for about 5 months now. Everything is going great. I have some grape corals, leather, bubble coral, a clown fish, two anthias, a wrasse,zebra eel, three shrimp and a whole cleaning crew. A couple of weeks ago I saw something try to eat the shrimp I was feeding my eel and finally identified it as a mantis shrimp. He is living in one of my live rock that is on the top part of my tank. I purchased a trap for it and have no success in trying to trap it. Any ideas on how I could trap this thing. I am trying to do this with out removing the rock because the coral that is attached to the rock is thriving and I really don't want to disturb it. Any help or suggestions, please!