A slim blue-grey damselfish of the offshore islands, feeding in open water above the rock rather than on it.
To about 17 cm. Slender and fusiform, steel blue to olive above and paler below, with orange on the throat.
The scissortail damselfish is the confusion and it has a white spot below the rear of the dorsal fin and blackish streaks in the tail lobes, neither of which this fish has, and no orange throat.
Five to thirty metres in open water around rocky reefs, feeding on zooplankton and pelagic fish eggs and larvae. No juvenile description was found.
Listed as Near Threatened. Its range is the southern California islands, Guadalupe, Cedros, Alijos Rocks and the Revillagigedos, so of the three eastern Pacific destinations on this site it belongs to Revillagigedo alone.
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.