Western Gregory

Plectroglyphidodon obreptus

The Western Gregory is a small reef-associated fish, reaching a maximum length of 12 cm. It has a distinctive appearance with a generally brown to nearly black body, which becomes paler towards the belly. The fins transition to a smoky gray at the edges, and the scales on its sides feature blackish streaks that form transverse bands. Small blue spots are scattered on its head and sides, while the pelvic and anal fins are bright blue at the front. Found in the Indo-Pacific region, its range extends from the Ryukyu Islands through the Indo-Malayan Archipelago to Western Australia, and eastward to Sri Lanka and India. This species inhabits shallow waters, typically between 2 and 10 meters deep, favoring rocky or dead reef areas where visibility can be reduced due to silting and wave action. Western Gregorys are territorial fish, often seen maintaining patches of filamentous algae on dead coral. They are oviparous, with distinct pairing during breeding. The eggs are demersal, adhering to the substrate, and the males take on the role of guarding and aerating them. Divers encountering this species might notice its territorial behavior, as it tends to stay close to its chosen patch of algae. The Western Gregory is currently listed as Least Concern on the IUCN Red List. Divers can expect to see this fish year-round in its natural habitat.