a Gold Rim Tang (also known as a Whitecheek Surgeonfish) is generally considered reef safe when properly cared for and fed, although some caution is advised as they may occasionally nip at larger polyp stony corals if not provided enough algae to graze on; making them best suited for experienced reef keepers. 
Key points about Gold Rim Tangs and reef safety:
Herbivore diet:
They primarily eat algae, which means they won't typically harm coral polyps.
Potential for coral nipping:
In some situations, especially if not fed enough algae, they may nibble on delicate corals, particularly large polyp stony corals.
Tank size requirement:
Due to their potential aggression, a large tank is recommended to accommodate their size and behavior.