I put a copperband in my tank a couple months ago, and he picked on the clams for a couple of days. Then he realized he had plenty of Aptasia to eat, and I have't seen him pick at a clam since. The only problem with copperbands is its really hit or miss whether you get one that survives on your tank. I've gotten lucky with this one, but you never know. Anyway, I hope this helps.
drew