Grey Demoiselle

Chrysiptera glauca

The Grey Demoiselle is a small reef fish found in the tropical Indo-Pacific region, ranging from East Africa to the Line and Pitcairn islands, extending north to Japan and south to Australia. It inhabits shallow waters, typically between 0 and 3 meters deep, often seen among rubble or consolidated reef rock on exposed intertidal reef flats and sandy beaches. This species is known for its fusiform body shape with an oval cross-section, and it can reach a maximum length of 11.5 cm. It has 13 dorsal spines, 12 to 13 dorsal soft rays, 2 anal spines, and 11 to 13 anal soft rays, which help in identifying it from similar species. Divers may encounter these fish in small groups, especially near freshwater run-offs, where they are active during the day. The Grey Demoiselle primarily feeds on benthic algae, contributing to its role in the reef ecosystem. This diurnal species is often seen grazing on algae during daylight hours. Reproduction involves distinct pairing, with the species being oviparous. The eggs are demersal and adhere to the substrate, where males take on the role of guarding and aerating them. The Grey Demoiselle is currently listed as Least Concern by the IUCN.