Diagnosis: Nothobranchius ivanovae males are similar to other members of the N. taeniopygus species group, differing from all other species of the genus by caudal and anal fin with a broad light sub-marginal band and dark margin (Ref. 92886). It differs from the similar and geographically closest N. taeniopygus from Ipati River by the following combination of characters: caudal fin red vs. pale brownish red, caudal fin with subdistal band vs. without band, anal fin with a creamy yellow broad submarginal band vs. thin white band; and from N. taeniopygus from Wogo River by the following combination of characters: blue-grey scales vs. light blue, caudal fin red vs. pale brownish grey, caudal fin with a subdistal and distal band vs. without band (Ref. 92886). In addition, N. ivanovae males have a relatively shorter head compared to N. taeniopygus "Ipati river", 29.5-34.6% of standard length vs. 33.0-37.5%; smaller eye, 22.8-29.0% of head length vs. 30.7-38.9%; more scales on lateral line, 31 vs. 28-30; and more dorsal and anal fin rays, 17-18 vs. 14-15 and 17-18 vs. 15-17 respectively (Ref. 92886). They have also a shorter head compared to N. taeniopygus "Wogo river", 29.5-34.6% of standard length vs. 33.6-35.4%; more scales on lateral line, 31 vs. 30; and more dorsal fin rays, 17-18 vs. 15 (Ref. 92886).