Hey all,
I've never tried a copperband in a reef tank, though I have kept a few in FOWLR tanks. My experience has been that they are peaceful fish, with great personalities. They do eat aiptasia with a vengance (at least mine have), but I've never kept them around any corals to I can't personally attest to their being coral-safe or not. They are very nice fish, though. [smiley=thumbs_up1.gif]
The MOST reef-safe butterfly, I believe, is the
Chaetodon sedentarius. Here's a pic from Fish Base:
Mostly known as the Reef Butterflyfish, the diet of these fish consists of,
"Prefers to feed on eggs of Abudefduf saxatilis (Ref. 9626) but also on polychaete worms, shrimps, amphipods and hydroids." also from FishBase.
Here's the link for more info:
http://www.fishbase.org/summary/Spec...ry.cfm?id=3605