This species is a member of the Oryzias woworae-species group which all share orange to deep red dorsal and ventral margins of the caudal fin and the ventral margin of the caudal peduncle and at least the posterior portion of the base of the anal fin, and a bluish sheen on the body in both sexes that is most pronounced in live adult males. Oryzias wolasi and O. asinua differ from O. woworae by having elongate middle dorsal-fin rays in males that reach the posterior extent of the first principal caudal-fin ray. Oryzias wolasi can be diagnosed by the following characters: golden in life in both sexes; relatively deep-bodied, reaching 32% SL (vs. reaching 25% in O. asinua and 30% in O. woworae); caudal peduncle depth 11-12 % SL, mean 11.2 (vs. 9-11, mean 10, in O. asinua and 8-11, mean 9.2, in O. woworae) (Ref. 94271).