Ray-finned Fishes of Zihuatanejo

CLASS ACTINOPTERYGII

-Cichlids, Damselfishes, and Allies (Order Cichliformes)

-Damselfishes (Family Pomacentridae)

-Sergeant Damselfishes (Subfamily Glyphisodontinae)

-Sergeant Majors (Genus Abudefduf)

-Panamic Sergeant Major (Abudefduf troschelii)

The Panamic Sergeant Major, Abudefduf troschelii, is a member of the Damselfish or Pomacentridae Family, and is known in Mexico as petaca banderita. The Panamic Sergeant Major is a non-migratory species found in shallow water over and within rocky reef structures buffeted by wave action at depths up to 15 m (50 feet). While breeding, males turn a very dark metallic blue to attract females to their nesting site, then guard and aerate the eggs.

Diet

Omnivorous reef fish that feeds mainly on plankton in the surface and mid-water, while also grazing on benthic algae and small invertebrates.
Its diet includes zooplankton, benthic microalgae, small crustaceans, worms, fish eggs, and fish larvae.

Range

Tropical eastern Pacific, ranging from the Gulf of California and the Pacific coast of Mexico south to northern Peru, including the Galápagos and other offshore islands.
It occurs along the Mexican Pacific coast, including Guerrero, and is within the Zihuatanejo region.

Habitat

Inhabits shallow rocky and coral reefs, usually in large aggregations.
Generally occurs from the surface to about 12–15 metres, although it may occasionally occur somewhat deeper.
Adults move above reefs and rocky substrate while feeding, often forming conspicuous schools in the water column.
During breeding, males establish small nesting territories on the reef and guard eggs attached to the substrate.

Description

Medium-sized damselfish with a deep, oval, laterally compressed body and a small protrusible mouth.
Typically has a silvery to whitish head and lower body, a yellowish back, and five prominent dark vertical bars across the sides.
A distinct black spot occurs at the base of the pectoral fin.
Adults can reach about 20–23 cm in total length.
Breeding males undergo a striking colour change, becoming noticeably darker and bluish during the nesting period.