The approximately 20 species of
Abudefduf may be divided into planktivores and benthivores and three broadly pantropical clades. Two of the
Abudefduf clades are primarily benthivorous and a third clade is composed of planktivores and is the most species-rich. Most diversification has occurred in the last 10 million years within this genus across all clades. In their native environment, sergeant majors are very abundant, often being one of the dominant species in a locale. Research indicates that some
Abudefduf species are undergoing range expansion towards more
temperate waters in Australia. ==Species==