The Achilles Tang, also known as the Red-tailed Surgeon, or Achilles Surgeonfish, is very dark brown to purple. It has bright highlights of white and orange around the dorsal, caudal, and anal fins. A white marking is also present on the gill covers and a striking orange teardrop is found near the caudal fin. The juveniles of this species have an orange marking by the tail in the shape of a streak instead of being teardrop in shape.