Two phenetic complexes are recognized among the small (usually less than 46 mm SL), semitranslucent, red species of the subgenus Apogon lacking stripes, bars, or black edges on scales on body sides, with six spines in first part of dorsal fin and one spine and 8–9 (almost always 9) rays in second part, two anal fin spines and 7–8 (almost always 8) rays, 12–15 pectoral fin rays, and a total of 16 or fewer gillrakers. The Apogon coccineus complex has one large full scale, and often one small scale, between the lateral line and the third spine of the first part of the dorsal fin and a free edge of skin near the anterior nasal opening. Members of the Apogon erythrinus complex have two large full scales, and often a small scale, between the lateral line and dorsal fin and no free edge of skin near the anterior nasal opening. Four species are recognized in the A. erythrinus complex: A. erythrinus, endemic to the Hawaiian Islands and Johnson Island; Apogon marquesensis n. sp., endemic to the Marquesas Islands; Apogon indicus n. sp., ranging from the Indian (where it is the only member present) to the Pacific oceans; and Apogon susanae n. sp., restricted to the Pacific Ocean.