Distinctive Characters: Dorsal fin with 13 spines and 21-23 rays. Anal fin with 3 spines and 16-18 rays. Pectoral fin with 14 rays. Body depth 1.5-1.6 in standard length.
Colour: Background colour olive. Black eye stripe and band through tail. Dusky band around caudal peduncle. Many small spots covering body and dorsal and anal fins arranged roughly in lines. Yellow margins to dorsal and anal fins.
Habitat and Biology: Inhabits, reef edge and upper reef slopes. Occurs singly, in pairs, or in small aggregations. Feeds mainly on polychaete worms, algae and coral polyps.
Distribution: Indian Ocean.
Remarks: Chaetodon guttatissimus might be confused with C. citrinellus, but the later is a paler, more yellow coloured species, with finer dotting and a characteristic black edged anal fin. C. guttatissimus is closely related to C. punctatofasciatus Cuvier and C. pelewensis Kner of the Pacific.