Bright blue with a black back margin and a deeply forked tail, feeding in clouds above the reef edge.
To about 15 cm. Dark electric blue with a black line along the upper back and black margins on the upper and lower edges of a deeply forked tail with sharp points.
The confusion is the purple reeffish, which has neither the black back line nor the black tail margins.
Three to sixty metres, usually ten to twenty, over large coral heads and drop-offs. It feeds on copepods in midwater aggregations above the reef and retreats into coral crevices when threatened, and it commonly mixes with creole wrasse in the same water. Eggs are laid on the bottom and the male guards and fans them.
The genus has moved: Azurina cyanea is the accepted combination and Chromis cyanea is superseded, though most field guides still print the old one.
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.