FORAGING BY MIXED-SPECIES GROUPS INVOLVING A SMALL ANGELFISH, CENTROPYGE-FERRUGATUS (POMACANTHIDAE)

Feeding ecology of the small angelfish Centropyge ferrugatus was studi ed at the coral reefs of Okinawa, Japan. This angelfish fed mainly on detritus and algae by nipping substrate within a small home range. In the breeding season, both sexes allocated usually about 60% of their t ime to foraging in the daylight hours, but females foraged more freque ntly than males. Centropyge ferrugatus frequently approached and follo wed similar-sized fishes of various species. Both sexes nipped more qu ickly and frequently in the association than in solitary foragings. Sm aller individuals (females) more frequently associated with other fish es. Circumstantial evidence suggested a high predation pressure on the angelfish. We suggest that the association provides an antipredatory benefit to the angelfish, and enables the angelfish to devote more tim e to feeding because of less time required for the vigilance against p redators.