Within the Pomacentridae family or also known as the family of damselfishes & clownfishes we find Chromis atripectoralis, one of the 387 species currently existing in this family, which is organized within 4 subfamilies and a total of 29 different genera. We find this species in the waters of the Indian Ocean and in the South Pacific Ocean, from the coasts of East Africa to French Polynesia, south of Japan. It inhabits coral reefs, among the branching colonies of corals, usually in shallow waters (less than 20-30 meters).
Chromis atripectoralis can reach sizes up to 12 cm. Its body is oval, relatively tall and laterally compressed. Its dorsal fin is single and consists of 12 spines followed by 9-10 soft rays, while the anal fin has 2 spines and 9-10 soft rays. The caudal fin is forked.
Both the head and flanks of Chromis atripectoralis are greenish-blue, while the belly is whitish to grayish.
The diet of Chromis atripectoralis is based on the capture during daylight hours of small crustaceans such as copeopods, amphipods.
Chromis atripectoralis is an oviparous species, which lays its eggs in the water column, where fertilization occurs and eggs are formed. Subsequently, larvae hatch from the eggs and become part of the plankton.
This species is often confused with Chromis viridis, due to the great morphological and chromatic similarity. However, to differentiate between these two species we have to look closely at the coloration of their fins. The intersection between the body and the pectoral fin, an area generally known as the pectoral axilla, is black in the case of Chromis atripectoralis, while in the case of Chromis viridis, although it is also dark, it is much more diffuse. Another characteristic that could also help in identification is the number of pectoral fin rays. In the case of Chromis atripectoralis they are 18-20, and in Chromis viridis they are 17-19.
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