Nothobranchius kardashevi males are similar to other members of N. ugandensis species group, differing from all other species of the genus by combination of male colouration characters consisting of light blue scales with a broad irregularly reticulated pattern on body forming oblique bars in bright red, vivid bright red colouration on the head and dorsum, yellow or blue anal fin, large vivid red spot pattern on dorsal and anal fins; rounded head, dorsal profile of head slightly concave to nearly straight, convex from nape to end of dorsal fin base; variable cephalic squamation (Ref. 92886). It differs from other members of the N. ugandensis species group by caudal fin spotted vs. caudal fin plain (Ref. 92886). It is distinguished from N. nubaensis by reduced red pigmentation, having irregular broad margin on scales vs. regular reticulation, by hyaline pectoral fins vs. red, and having blue anal fin and pelvic fins vs. yellow (Ref. 92886). It is distinguished from N. ugandensis by absence of dorsal, anal and caudal fin margin vs. present, by broad irregular blotch pattern on dorsal fin in two colours vs. only one colour and more regular pattern often reduced as a series of dots, by anal fin pattern with large irregular spots in two colours vs. without any spots or if present in only one colour and reduced to a few dots, by broad spots on caudal fin vs. if present faint dots on yellow morph (Ref. 92886). In addition, N. kardashevi males have a relatively longer head compared to N. nubaensis, 31.2-34.6% of standard length vs. 26.3-33.6%; relatively higher number of scales in longitudinal series, 28-32 vs. 29-30, fewer anal fin rays, 16-17 vs. 17-19, more slender caudal peduncle compared to N. ugandensis, 12.1-13.0% of standard length vs. 12.5-16.2%; reduced number of circumpeduncular scales, 12 vs. 14 in N. nubaensis and 14-16 in N. ugandensis, and a different posterior supraorbital neuromast series, with two neuromasts vs. three in N. ugandensis and N. ugandensis (Ref. 92886).