Scissortail damselfish

Appearance

Metallic grey with prominent white spot just below end of base of soft dorsal fin; each caudal fin lobe with intensely blackish streak, a blackish mark at base of pectoral fin. Size: attains 13 cm.
Body compressed, elongate, greatest body depth 2.3-3.7 in SL; 1 pair of nostrils; edge of bone under eye smooth; preopercle smooth or with occasional fine serrations; mouth small, protrusible, opens at front; teeth in 2 rows, outer conical, larger; lower gill rakers 20-23; a single continuous dorsal fin, XII, 12-13; anal rays II, 10-12; pectoral rays 18-19; 2-3 short projecting spines at upper and lower base of tail fin; caudal fin forked, with sharp tips; scales large and rough; 20-21 lateral line scales; body scaled, most of head scaled, basal parts of the median fins scaled; lateral line incomplete, ends under end of dorsal fin base.

Distribution

Eastern Pacific: northern Gulf of California to northern Peru, including the Galapagos and Cocos islands.
Tropical; 33°N - 18°S

Status

Least Concern.

Behavior

Not strongly territorial as other damselfishes in the area. They become almost invisible in the darkness of deep water except for its brilliant post-dorsal white spot which gives the illusion of glowing in the dark.

Habitat

Marine; reef-associated; non-migratory; depth range 6 - 80 m, usually 6 - 20 m.
Adults inhabit coral or rocky reefs.

Reproduction

Oviparous, distinct pairing during breeding. Eggs are demersal and adhere to the substrate (Ref. 205). Males guard and aerate the eggs.

Food

They aggregate in large numbers in open water above reefs and feed on zooplankton.