With vivid vertical striations of blue, white, yellow, or orange on the body and pelvic fin, the Regal Angelfish deserves this distinctive name. Regal Angelfish from the Maldives and the Red Sea have a distinctive yellow breast, where their Indo-Pacific, Coral Sea, and Tahitian relatives normally have a blue/gray breast. This coloration is more prevalent in specimens that are more mature and are at least 4" in length. Juveniles will have a "False Eye Spot" on their dorsal fins that fades and the fish matures.
The Regal Angelfish is more difficult to maintain than other species of angels so it should be introduced first so that it may stake out its territory in advance of other fish. A minimum of a 125 gallon tank with plenty of hiding places and live rock for grazing will offer a good environment.
Source: Live Aquaria - Photo used as indicative only.