While I was looking over my tank today, deciding wheather or not to vacuum I saw something odd in one of my caves. I saw a black claw reached out. I knew I had a rock crab from moltings, but this was the first time I had seen him. By the looks of it he was waiting for lunch to pass by. I lured him out with some shrimp and then got him with a scewer, not the most humane way to remove him but he had to go.