They will probably eat all your shrimp even cleaner shrimp) my wife called one of my Shrimp Killer, they will eat all of your snails and crabs. They like to turn over corals looking for food. I have one now, he can out eat as much as the rest of the fish in my tank. They are docile usually afraid, my last HT was so shy he would hide when I walked up to the tank, but of course that is when I feed, so he missed a lot of meals. Great fish but they can have all different personalities.