The Blue Line Grouper (Cephalopholis polleni), also known as the Harlequin Hind or Harlequin Grouper, is a species of marine ray-finned fish from the family Epinephelidae.

Distribution and Habitat

The Blue Line Grouper has a scattered distribution on offshore islands in the Indian Ocean and Western Pacific Ocean from the Comoro Islands to the Line Islands and French Polynesia. It occurs around oceanic islands in clear waters in the vicinity of steep drop-offs at depths of 30 to 120 meters.

Physical Description

The Blue Line Grouper is a yellow to greenish-yellow grouper which is covered in bright blue stripes. Juveniles are yellowish brown with horizontal purple stripes on the head and body. The maximum recorded total length is 43 cm (17 in).

Diet and Feeding

This is a solitary predatory species which feeds on smaller fishes and crustaceans. In captivity it should be fed a variety of meaty foods including fish and shrimp.

Behavior and Reproduction

The Blue Line Grouper is solitary and is frequently observed in caves and under overhangs where it swims upside-down against the roofs of caves or archways. It is a secretive species.

Aquarium Care

It requires a tank of at least 100 gallons with plenty of caves and overhangs for hiding. It is semi-aggressive and should be kept with similarly sized or larger tankmates. It will eat smaller fish and should not be housed with small peaceful species.

Conservation Status

Classified as Least Concern by the IUCN Red List.