This species is distinguished by the following set of characters: pored lateral-line scales 11-16+3-10, often 16+5-7; gill rakers usually 12-13 (sometimes 14-15); body depth 2.9-3.5 in SL; often, 4-6 (rarely 3) dorsal soft rays of males prolonged as narrow, tapering filaments that are erected during courtship; in males, caudal fin strongly lunate, the length 1.6 (1.7-2.4) in SL and caudal concavity 0.8-1.5 in HL; pelvic fins 1.6-1.8 in males and 2.0-2.2 in females, both in HL; live colour of male differs from all other Paracheilinus in having a pair of rectangular blackish patches, one on ventral half of caudal peduncle and adjacent body, and the other, often less distinct, on upper back, below middle of spinous dorsal fin. Similar to P. cyaneus in general appearance; sympatric throughout its known range (Misool, Fak Fak Peninsula, and Triton Bay area). The two species are easily distinguished on the basis of male coloration, particularly that associated with courtship displays (Ref. 74967).