The queen angelfish (Holacanthus ciliaris), also known as the blue angelfish, golden angelfish, or yellow angelfish, is a species of marine angelfish found in the western Atlantic Ocean. It is a benthic (ocean floor) warm-water species that lives in coral reefs. It is recognized by its blue and yellow coloration and a distinctive spot or "crown" on its forehead. This crown distinguishes it from the closely related and similar-looking Bermuda blue angelfish (Holacanthus bermudensis), with which it overlaps in range and can interbreed. Adult queen angelfish are selective feeders and primarily eat sponges. Their social structure consists of harems which include one male and up to four females. They live within a territory where the females forage separately and are tended to by the male. Breeding in the species occurs near a full moon. The transparent eggs float in the water until they hatch. Juveniles of the species have different coloration than adults and act as cleaner fish. The queen angelfish is popular in the aquarium trade and has been a particularly common exported species from Brazil. In 2010, the queen angelfish was assessed as least concern by the International Union for Conservation of Nature as the wild population appeared to be stable. Taxonomy The queen angelfish was first described as Chaetodon ciliaris in 1758 by Carl Linnaeus in the 10th edition of his Systema Naturae, with the type locality given as the "Western Atlantic/Caribbean". In 1802 it was moved by French naturalist Bernard Germain de Lacépède to the genus Holacanthus, the name of which is derived from the Ancient Greek words "holos" (full) and "akantha" (thorn). Its specific name ciliaris means "fringed", a reference to its squamis ciliatis ("ciliate scales"). Other common names for the species include "blue angelfish", "golden angelfish" and "yellow angelfish". Marine angelfish of the genus Holacanthus likely emerged between 10.2 and 7.6 million years ago (mya). The most basal species is the Guinean angelfish (Holacanthus africanus) off the coast of West Africa, indicating that the lineage colonized the Atlantic from the Indian Ocean. The closure of the Isthmus of Panama 3.5–3.1 mya led to the splitting off of the Tropical Eastern Pacific species. The closest relative and sister species of the queen angelfish is the sympatric and similar Bermuda blue angelfish (H. bermudensis), from which it split around 1.5 mya. They are known to interbreed, producing a hybrid known as the Townsend angelfish which has