A dark damselfish with a pale tail, restricted to the offshore islands of the eastern Pacific.
To about 17 cm. Dark brown with darker scale outlines and usually a white band across the tail base. The juvenile differs in having an olive-green nape, upper back and spiny dorsal. Adult males carry a dense covering of microscopic papillae on the outer half of the pectoral fin, which is a museum character rather than a field one.
Colour will not separate it from the Galapagos ringtail damselfish — the two descriptions are nearly word for word the same — so geography does: this fish is Guadalupe, Revillagigedo and Baja, and that one is the Galapagos, Cocos and Malpelo. At Revillagigedo the real pair is the Clarion damselfish, which has a pale yellow tail and a whitish rear body where this one is uniformly dark.
Nought to eighteen metres on rocky reef. An omnivore taking benthic microalgae, shrimps, crabs and sessile worms. Territorial defence has not been recorded for it specifically.
Listed as Vulnerable.
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.