Regal angelfish
(Pygoplites diacanthus)

The royal angelfish (Pygoplites diacanthus), or regal angelfish, is a species of marine ray-finned fish, a marine angelfish belonging to the family Pomacanthidae, and the monotypic genus Pygoplites. It is found in tropical Indo-Pacific oceans. It can grow as long as 25 cm.

The body of the royal angelfish is moderately elongate and is very compressed. The preorbital bone convex and has no strong spines. There is 1 prominent spine at an angle at the preopercal. The ventral edge of the interopercle is smooth. The eyes are moderately small along with the mouth that is terminal. The mouth is also protractile.

They have a total of 14 dorsal spines, and 17-19 soft dorsal rays. They have 3 anal spines and 17-19 anal soft rays. They also have 16-17 pectoral fin rays.

Their caudal fin is rounded.

The precise coloration of this fish can vary as regional differences can occur, most notably in populations from the Indian Ocean, Red Sea, and South Pacific Ocean. A commonality, however, is a body edged in narrow blue-white and orange stripes that are narrow and angle backward. The posterior portion of dorsal fin is black or blue with close-set blue dots, and the posterior portion of anal fin has alternating yellow and blue bands running parallel to body contour. The caudal fin is yellow. Juveniles are colored with a large dark spot on basal portion of the soft dorsal fin.[3] They have been reported of living 15 years.

Recent research indicates that the Pygoplites comprises two morphs, with the variants potentially hybridizing at Christmas Island.