I have the option to get a nice colored pretty tame tusk for a few coral trades. He would go in my 120g reef and is about 5" long. I have a cleaner shrimp which would have to find a new home I guess, but I am worried about my small fish. I have a pair of clowns, fairy wrasse, watchman goby and a royal gramma. I also have a 4" clam as well. So they don't pick on ANY corals?