The only angelfish here that feeds in mid-water, and the sexes are coloured differently.
To about 18 cm, with a deeply forked tail edged in yellow. Males are pale yellow-green with about fifteen narrow dark vertical bars and a black spot on the chest; females are plain blue-grey above and yellow below with a black-edged tail and no bars. The sexes were long recorded separately.
Unlike other angelfishes, which pick sponges and tunicates off the reef, Genicanthus feeds on zooplankton in open water, and the forked tail goes with that. Groups of a male and several females hang off steep walls, generally below 15 m and often below 30 m, and drop deeper when approached. That depth is the practical constraint on photographing them. Recorded to about 60 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.