Three-spot Dascyllus

Overview

The Three-spot Dascyllus, also known as the domino damselfish, is a widely distributed reef-associated fish found throughout the tropical Indo-Pacific. It is a gregarious, diurnal species often observed in small to large aggregations around coral and rocky reefs.

Distribution & habitat

This species is found from the Red Sea and East Africa across the Indo-Pacific to the Line and Pitcairn Islands, extending north to southern Japan and south to Sydney, Australia. It is notably absent from the Hawaiian and Marquesan islands. Adults typically inhabit coral and rocky reefs, while juveniles are frequently found in commensal relationships with large sea anemones, sea urchins, or small coral heads for protection.

Appearance

This fish has a deep, compressed body with a rounded profile. Juveniles are distinctively black with bluish scale centers and three prominent white spots—one on the forehead and one on each upper side. As the fish matures, these spots fade significantly or disappear entirely, and the body color often shifts to a darker grey or black. The fins are generally dark, with the exception of the pectoral fins.

Biology & behavior

As a diurnal and social species, it is often seen swimming in groups. During the breeding season, males perform "signal-jumping" courtship displays to attract females. They are known to emit sounds for defense or during reproductive interactions. The species follows a typical bipartite life history, involving a site-attached adult phase and a pelagic larval stage.

Feeding

These fish are planktivores that feed in the water column. Their natural diet primarily consists of copepods, various planktonic crustaceans, and algae.

Reproduction

They are oviparous, batch spawners that exhibit distinct pairing during breeding. Males are responsible for guarding and aerating the demersal eggs, which are attached to the substrate.