Do a search for mantis. They are inverts that will eat your shrimp, snails, crabs, and fish. They live in the lr. You will need to get rid of it because it will keep eating fish. Just be careful when messing around in the tank....they bite very hard. You will have to find what piece of lr he lives in, and take it out and pour soda on it or put in water w/ a very high specific gravity to get it out. good luck