In reality, NONE of the butterfly fish are 100% reef safe. Even the copperbanded butterflyfish can/will eat your tube worms, feather dusters, and maybe even some coral polyps...
Here's what Bob Fenner at WetWebMedia says about the Golden:
"Amongst a mix of suitable species of Butterflyfishes hailing from the area, the Blue Mask or Semilarvatus (Chaetodon semilarvatus) Butterfly ranks supreme. It is superlatively suited for captive use amongst its family members in the Red Sea; accepting worm, crustacean, small mollusc and zooplankton type foods, bearing up well under conditions of capture, holding, shipping and processing, and in more modern times, coming down in price to suit a broader range of pocketbooks. About the only trait/characteristic working against its selection, is its "up to plate size" potential growth."
C. semilarvatus
and:
Chaetodon semilarvatus Cuvier 1831, the Golden or Blue-Mask Butterflyfish. Only found in the Red Sea south into the Gulf of Aden. To plate-size, nine inches or so. Omnivore that does eat coral polyps, soft and hard species.
Chaetodon
While they are hardy fish that usually adapt to aquarium life pretty well, they are NOT in the "reef-safe" category...