A two-and-a-half month collection expedition to the Chagos Archipelago, central Indian Ocean, plus two other smaller collections made in 1980 and 1985, yielded specimens of 585 species of fishes, with an additional 16 species seen but not collected. A further 100 species are recorded from literature,and 2 additional species from Chagos were discovered in the collections of the British Museum (Natural History).