I've had one for almost a year and I've never had him go after an Sps. Not that it can't happen. I was infested with majano's. After they were gone he went after my brown button polyps. No problem there. I'm actually looking for another for my sump. Since it is infested with majano's. Thought of trapping it.
Tom
Speaking of CBB, i saw one in AquaHut today. Seemed quite active and healthy. It was no bigger than 4" max.CBB = Copper Banded Butterfly