Sergeant-major(Abudefduf biocellatus)
is a small, oval-shaped damselfish known for its five vertical black bars on a silvery or yellowish body, resembling military insignia. During the breeding season, males turn a dark blue-gray. They are omnivorous, live in small groups, and are found in tropical and subtropical reef environments around the world, particularly in the Atlantic, Indian, and Pacific Oceans.