Diagnosis: Nothobranchius hoermanni belongs to the N. ugandensis species group presenting the following combination of characters in males: body colouration light blue with red to red-brown scale margins; frontal part of head red-brown and throat light blue or red; caudal fin uniform red; anal fin light blue or yellow with red-brown spotted pattern (Ref. 123150). Nothobranchius hoermanni differs from all other members of the N. ugandensis species group by a red throat; light blue anal fin with red-brown spots and stripes proximally and medially, and broad light blue distal zone without markings; pectoral fin hyaline with red-brown stripes parallel to fin rays; exposed branchiostegal membrane red-brown, with cream distal margin; suborbital depth 28% of head length vs. 19-27% (Ref. 123150).

Description: Medium size Nothobranchius species, maximum recorded size 50.5 mm standard length; general body shape robust, laterally compressed and deep; greatest body depth at vertical in front of pelvic-fin origin, 30.9% of standard length; greatest body width at pectoral-fin base with body progressively narrowing towards caudal-fin base (Ref. 123150). Dorsal profile slightly convex from tip of snout to base of last dorsal-fin ray, straight on caudal peduncle; ventral profile convex from lower jaw to base of last anal-fin ray, straight on caudal peduncle; caudal peduncle moderately deep, length 135% of its depth; anus situated directly in front of anal-fin origin (Ref. 123150). Head moderately long, 27.7% of standard length, laterally compressed, deeper than wide, head width 73% of its depth; snout slightly pointed, smaller than eye diameter; mouth supraterminal, slightly oblique in profile; jaws subequal, lower jaw longer than upper, posterior end of rictus at same level or slightly ventral to centre of eye; premaxilla and dentary with many irregularly distributed conical teeth on inner rows and slightly curved teeth on outer row; eye diameter 29% of head length, entirely in anterior half of head, snout to eye end length 43% of head length; branchiostegal membrane projecting posteriorly from opercle (Ref. 123150). Dorsal-fin origin slightly anterior to anal-fin origin, both fins originating posterior to mid-length of body, predorsal length 59.6% of standard length, preanal length 60.6% of standard length; extremity of dorsal and anal fins rounded, with small contact organs in form of papillae on fin rays and distal margin with short filamentous rays; posterior extremity of dorsal fin reaching caudal-fin base; dorsal fin with 16-17 rays; anal fin with 15-16 rays; pectoral fin subtriangular, insertion slightly posterior to margin of opercular opening, base slightly oblique, upper fin rays positioned slightly anteriorly to lower fin rays, its tip reaching or slightly overlapping base of pelvic fin; pelvic fin subabdominal, origin at about mid-length of body, short, base medially separated, its tip reaching urogenital papilla; caudal fin subtruncate (Ref. 123150). Scales cycloid, body and head entirely scaled, except for ventral surface of head; no scales on base of dorsal and anal fins; scales in mid-longitudinal series 29-30 plus two or three small scales on caudal-fin base; transverse rows of scales in front of dorsal-fin origin 11; scale rows around caudal peduncle 14 (Ref. 123150). Cephalic squamation pattern variable; frontal neuromasts separate in two rows of shallow grooves behind the upper lip, with one neuromast in each groove; cephalic sensory system at supraorbital level fragmented in two discontinuous shallow grooves with four exposed neuromasts in each portion; at supratemporal level with five exposed neuromasts in undivided, slightly curved shallow groove; preorbital canal in shallow groove with three exposed neuromasts; infraorbital level with series of about twelve exposed neuromasts or small buttons at ventral and posterior margin of orbit, as a continuous part of preorbital canal; postorbital canal in deep groove with two exposed neuromasts; preopercular system with exposed neuromasts in deep groove on preopercle portion; in shallow groove with exposed neuromasts and small buttons on ventral portion; mandibular canal in shallow groove with about ten small buttons; one neuromast on each scale along trunk mid-longitudinal series (Ref. 123150).

Colouration: Colouration of live male: scales on trunk and head light iridescent blue with red margins, forming a regular reticulation pattern; scales on abdomen faint blue; scales on dorsum anterior to dorsal fin with wider red margins, conferring an overall darker appearance towards the head; snout, frontal portions of head and throat red; posterior scale margins on post-orbital portion of opercle forming two to three red oblique bars; iris golden; exposed branchiostegal membrane red-brown, with distal margin cream; dorsal fin light blue with red-brown stripes parallel to fin rays; anal fin light blue with red-brown spots and stripes proximally and medially, and with broad light blue distal part; caudal fin uniform red; pelvic fin light blue with red brown dots proximally; pectoral fin hyaline with red-brown stripes parallel to fin rays and narrow light blue distal margin (Ref. 123150). Colouration of live female: trunk and head light grey-brown, darker on dorsum and lighter ventrally; scales with a very narrow grey margin; scale centres iridescent silver to very pale blue; all fins hyaline; iris golden (Ref. 123150).