Steve, we have had a CBB for about two and half years in tanks that have had every kind of coral or invert you can imagine. (softies, lps, sps, clams, shrimp, crabs, hermits, ...) In the first couple of days he consumed ever aiptasia and fan worm in the tank. The only other inhabitants he picked on were clams, relentlessly until I removed them. We had frogspawn and hammers and he never touched either. Like Stu, we had a green candy cane that he never touched but we didn't have the pearl so I can't speak to that one.
He has never bothered anything else. He did try some Elongata Xenia twice but unfortunately he didn't like it. He is currently being kept by another reefer (Dave) who has him in a sump with coral frags and either a LTA or BTA and to my knowledge he hasn't bothered either. He is somewhat of a pill spitting water at Dave when he is hungry (which is all of the time), eating from your hand, and following you around the tank like a dog.
Funny story - When we moved him from the 180 to Dave's sump he was the last fish to be removed. I put the fish trap into the tank and went to the fridge to get the mysis, when I returned he was sitting in the trap waiting for me to feed him. IMO, great fish. You do need to be careful when selecting a CBB. Make sure you get a larger specimen and have the employee feed it while you watch. They are usually picky eaters and many starve in our tanks; I have had the best success using PE Mysis.