Green damselfish

The green damselfish (Abudefduf abdominalis), also known as the Hawaiian sergeant major, is a non-migratory fish of the family Pomacentridae. It occurs in the Pacific Ocean in the vicinity of the Hawaiian Islands, Midway Island and Johnston Atoll. It can grow to a maximum total length of 30 cm.

Adults of the species are typically found in quiet waters with rocky bottoms in inshore and offshore reefs at a depth of 1 to 50 m, although juveniles may sometimes be found in surge pools. It is a benthopelagic species, with adults being known to form schools. The species feeds on a variety of algae and zooplankton. It is known to be used as a food source for humans in Hawaii. It occasionally appears in the aquarium trade.

Breeding
Abudefduf abdominalis is oviparous, with distinct pairing occurring during breeding. Eggs are demersal and adhere to the substrate, with males guarding and aerating the eggs. Breeding cycles depend on the availability of food. It is known to hybridise with Abudefduf vaigiensis which has been introduced to Hawaiian coastal waters.