Allen’s Damselfish (Pomacentrus alleni), also known as the Andaman Damselfish, is a species of damselfish from the Eastern Indian Ocean. It occasionally makes its way into the aquarium trade.

Distribution and Habitat

Allen’s Damselfish is found in the Eastern Indian Ocean. Adults inhabit rubble and dead reef of outer slopes and inshore areas at depths of 3 to 30 meters.

Physical Description

Allen’s Damselfish grows to a size of 6 cm (2.4 in) in length. It has a vibrant blue coloration typical of the Pomacentrus genus.

Diet and Feeding

Allen’s Damselfish is omnivorous, feeding on zooplankton and benthic algae. In captivity it accepts a varied diet including flakes, brine shrimp, mysis shrimp, and frozen preparations.

Behavior and Reproduction

This species is semi-aggressive and territorial. Like other damselfish it is a sequential hermaphrodite with a size-based dominance hierarchy.

Aquarium Care

It requires a tank of at least 20 gallons with abundant live rock for hiding. It is considered reef-safe. It should be kept singly or in established pairs.

Conservation Status

Classified as Least Concern by the IUCN Red List.