A small Red Sea damselfish with a dark bar behind the head, living among the branches of one coral head.
To about 6 cm. Whitish with a dark spot just behind the gill cover, black edging on the dorsal fin, and black pelvic and anal fins. It has no vertical body bars, which is the point.
The Red Sea humbug is the confusion and it is boldly barred black and white. Note that the Red Sea humbug is Dascyllus abudafur, split from D. aruanus on genetic and morphological grounds, so records under the old name need updating.
One to fifteen metres, permanently associated with a host coral — usually Stylophora pistillata, also Acropora and Porites — in groups of two to twenty-five. It hovers just above the colony picking drifting zooplankton and drops into the branches when threatened, and it sleeps in them. Group members hold separate stable feeding spaces within the colony. It is monogamous.
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.