The orange cloud over a reef slope; one male to several dozen females, and the male was one of them.
Females reach about 10 cm and are plain orange-gold with a violet line running from the eye to the pectoral fin base. Males reach about 15 cm and are magenta-purple with an elongated third dorsal spine, a red blotch on the pectoral fin and a strongly lunate tail. The two are so different that a group reads as two species until the male turns.
Groups form harems around a coral head or a stretch of wall, feeding on zooplankton carried past by current and dropping back into the coral when a predator passes. All fish begin as females; when the male is lost, the dominant female changes sex over a period of days, beginning with behaviour and finishing with colour. Numbers are much higher on current-exposed reef than on the sheltered slopes of most muck sites. Recorded from about 5 to 45 m.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.
