I got a Copperband from LiveAquaria.com and it is eating like a pig. I think the key to feeding is to offer a large variety to see what it likes. I have had mine for 8 weeks now and it has yet to bother my mushrooms or polyps. But...it is not considered 100% reef safe so it can be a crap-shoot. They are truely an awesome fish!
Some people are like slinkies...they serve no real purpose yet can still bring a smile to your face when you push them down the stairs!:p
Have a great day! Brian