My pistol shrimp has grown A LOT since I got him with my live rock 1 year ago. He may have tripled in size, and yet I only see him once every couple of months. He hides in my rock and moves the sand around. I didn't realize until the rocks on my left side of hte tank started sinking. I don't mind him, its just that I want to get another cleaner shrimp, but I fear what he will do to him. I thought about a mantis shrimp trap, but not sure if that would work.