Threespot Angelfish

Overview

The Threespot Angelfish (Apolemichthys trimaculatus) is a vibrant, reef-associated marine fish widely distributed across the tropical Indo-Pacific. Known for its striking yellow coloration and distinctive markings, this species is typically encountered as a solitary individual or in small, loose groups near coral structures.

Distribution & habitat

This species inhabits a vast range extending from the East African coast across the Indian Ocean to the western Pacific, reaching as far east as Samoa and as far north as southern Japan. They are commonly found in lagoons and on seaward reef slopes, often near coral, at depths ranging from 3 to 80 meters. While adults frequent moderate depths, juveniles are more secretive and typically reside in deeper crevices below 25 meters.

Appearance

Adults are characterized by a bright, lemon-yellow body that is strongly compressed laterally. Key identifying features include vivid blue lips, a black spot on the forehead, and a fainter, ocellated dark spot located behind the gill cover. The anal fin features a broad white zone bordered by a distinct black margin. Juveniles differ significantly in appearance, displaying a thin black vertical band through the eye and golden bars on their flanks, as well as a false eye-spot on the dorsal fin.

Biology & behavior

Threespot Angelfish are protogynous hermaphrodites, meaning they are born female and can transition into males as they mature. During the breeding season, they often form haremic groups consisting of one male and several females. They are known to hybridize with related species, such as A. xanthurus, in parts of their range.

Feeding

This species is primarily a grazer, feeding mainly on sponges and tunicates found within the reef environment.