Thanks...The Tusk does not bother any corals but I tried to add a couple of cleaner shrimp and they were just expensive food. The Tusk hit them almost instantly. He once tried to take a piece of fish from the nem but he got a face full of sting and swam around shaking his head and yawning his jaws. Would have been funny if I was not so worried about him being stung. He learned his lesson and does not go near the nem anymore.