Sergeant Major

The Sergeant Major is one of the most widely recognized and abundant reef fish in the Atlantic Ocean, named for the five bold black vertical bars on its flanks that resemble the chevron insignia of a military sergeant. The body is a greenish-yellow to silvery hue with the characteristic dark bars creating a distinctive and instantly identifiable pattern. This robust species reaches about 7 inches in length and is a common sight on virtually every reef, pier, and rocky shoreline throughout the tropical and subtropical Atlantic.

In the wild, Abudefduf saxatilis is found from the coast of West Africa across the Atlantic to the Caribbean, Florida, Bermuda, and south to Brazil. It is among the most ecologically versatile damselfish, inhabiting coral reefs, rocky shores, mangrove roots, pilings, and even floating debris far offshore. Sergeant Majors are omnivorous, feeding on zooplankton, algae, small invertebrates, and virtually anything edible they encounter. Males turn a deep blue-purple during breeding season and aggressively guard nests of purple eggs laid on hard surfaces.

While extremely hardy and easy to keep alive, the Sergeant Major's large adult size and aggressive territorial behavior make it a challenging community aquarium resident. Males in particular become highly combative during breeding condition, attacking any fish that approaches their territory regardless of size. A minimum of 55 gallons is recommended, and tankmates should be robust species capable of withstanding occasional chasing. The species is reef-safe and does not harm corals or invertebrates, making it suitable for fish-only or reef systems with appropriately matched companions.