Diagnosis: Nothobranchius nubaensis can be distinguished from all other species of the genus by the following combination of characters: 17-19 dorsal fin rays; 17-19 anal fin rays; 29-30 scales in median lateral series; dorsal and anal fin with short filamentous rays in males; pelvic fins short, tips reaching the anus; orange-red head with 3 distinct oblique bars on the operculum; dorsal fin light blue with a pattern of irregular orange-red spots and elongated yellow spots in distal areas; anal fin yellow, light blue at base, with a pattern of orange-red spots; pelvic fins yellow with a pattern of orange-red spots; pectoral fins orange-red with a light blue margin; caudal fin orange-red, with short pale or dark red lines extending from fin base onto fin rays (Ref.82677).

Description: Robust, deep bodied Nothobranchius with rounded snout; terminal mouth directed upward (Ref. 82677). Dorsal fin rays 17-19; anal fin rays 17-19; scales in median lateral series 29-30+2-3 on caudal fin base; cephalic squamation pattern variable (Ref. 82677). Anterior neuromast series of 'open' type; central series in shallow groove with low lobes and with 3 neuromasts; posterior cephalic neuromast series curved with 3 neuromasts; preopercular neuromast system in open groove, distal ridge overlapping opercle slightly; one neuromast on each scale of median longitudinal series (Ref. 82677). In males, body deep and moderalety compressed; dorsal profile slightly concave to nearly straight on head, convex from nape to end of dorsal fin base; ventral profile convex, slightly concave on caudal peduncle posterior to dorsal and anal fins; maximum body height occurring at the base of the pelvic fins; dorsal and anal fins shallow and rounded, tips with short filamentous rays; dorsal and anal fins with papillate contact organs, distributed over fin rays; pelvic fins short, tips reaching the anus; caudal fin subtruncate; branchiostegal membrane projecting from opercle, distal edge slightly wrinkled (Ref. 82677). Female smaller than male; body less compressed and less deep than in males; dorsal fin rounded; anal fin triangular with rounded tip; anal fin positioned more posterior; short snout and narrower caudal peduncle than in males; opercular membrane not projecting from opercle (Ref. 82677).

Colouration: Males with body and head scales light blue with broad orange-red margin, creating a reticulated pattern on body; almost completely orange-red on head; lips, snout, throat, frontal and superior portion of head all orange-red; opercular region with three distinct oblique bars on the operculum, extending from the eye to the upper part of the head; branchiostegal membrane orange-red with light blue rim; dorsal fin light blue with broad dark red reticulation, forming approximately horizontal arch-like stripes, broad border with interrupted red pattern; some elongated yellow spots in distal areas; anal fin yellow, light blue at base, with pattern of large orange-red spots; spots in the middle of the fin dark red, distal spots orange-red; caudal fin orange-red with pale or dark red lines extending from base onto fin rays, some specimens having a faint dark red marginal band; pelvic fins yellow with orange-red spots, spots near base dark red; pectoral fins orange-red with light blue margin, some specimens with yellow spots and short dark or pale red lines extending onto fin rays; iris golden, with faint black vertical bar through center of eye (Ref. 82677). Females with body pale olive-brown, lighter brown to silvery ventrally; unpaired and paired fins hyaline; iris golden, with faint black vertical bar through center of eye (Ref. 82677). In alcohol males with body scales light brown to whitish, almost all scales with distinct red margin; dorsal and anal fins light brown to whitish with a pattern of red spots; caudal fin of a light pale red; pelvic fins light brown to whitish with red spots near base; pectoral fins of a light pale red; iris bluish (Ref. 82677). Females in alcohol with body light brown to whitish; opercular and ventral area yellowish; unpaired and paired fins whitish; iris bluish (Ref. 82677).