Diagnosis: Nannocharax luapulae can be distinguished from all its congeners by the following unique combination of characters: its body colouration, which consist of 8 to 10 vertically ovoid or rounded black blotches that overlie a longitudinal mid-lateral black stripe vs. largely unpigmented body with only a black spot at the base of the caudal fin in N. hastatus, N. maculicauda and N. ocellicauda, six or seven rounded, well-spaced, mid-lateral black spots in N. gracilis, 17 black bars in N. fasciolaris, a broad black longitudinal band running on flanks along two rows of scales in N. latifasciatus, or a thin black lateral band covering only the lateral line scales, extending from snout to median rays of caudal fin in N. taenia; a completely pored lateral line vs. incompletely pored in N. angolensis, N. dageti, N. lineostriatus, N. machadoi, N. minutus, N. monardi, N. multifasciatus, N. rubensteini, N. uniocellatus and N. wittei; 49-55 lateral line scales vs. 38-40 scales in N. altus, 40-45 scales in N. ansorgii, 37-40 scales in N. brevis, 38-42 scales in N. fasciatus, 37-43 scales in N. hadros, 42 scales in N. hollyi, 45-48 scales in N. macropterus, 36-37 scales in N. micros, 36 scales in N. ogoensis, 36-40 scales in N. parvus, 38-43 scales in N. procatopus, 38 scales in N. pteron, 46-48 scales in N. reidi, 46-48 scales in N. signifer, 38-39 scales in N. schoutedeni, 43-44 scales in N. seyboldi, 38-44 scales in N. usongo and 39-43 scales in N. zebra; and a dorsal-fin origin that is situated anterior, 1-2 lateral line scales, to the pelvic-fin origin vs. origin situated well behind the pelvic-fin origin in N. lineomaculatus, N. rubrolabiatus, or at the same level in N. elongatus, N. intermedius, N. niloticus and N. occidentalis (Ref. 129519). Nannocharax luapulae is most similar to N. chochamandai but can be distinguished from it by a low number of branched soft fin rays in dorsal and anal fins, 9-10 and 5 vs. 11-12 and 8-9; a high number of lateral ine scales, 49-55 vs. 41-46; a short pectoral fin, 18.3-20.6% of standard length, not reaching the pelvic-fin insertion but extending to the level of the anterior dorsal-fin base origin, vs. 21.6-28.4% of standard length, reaching the pelvic-fin insertion and the level of about the middle of the dorsal-fin base; a short pelvic fin, 20.0-22.9% of standard length, not reaching the anal-fin insertion but extending to about mid-level of the dorsal-adipose fin distance, vs. 24.3-30.6% of standard length, reaching the anal-fin insertion and the level of the last one fourth of the dorsal-adipose fin distance; and a short anal fin, 13.6-15.1% of standard length vs. 15.6-19.0% (Ref. 129519).

Description: Body slightly elongated and laterally compressed, oval in cross-section; profile of predorsal region convex; body profile straight to slightly convex from insertion of last dorsal-fin ray to caudal-fin origin; lower part of body convex; maximum body depth reached just in front of dorsal-fin origin (Ref. 129519). Head anteriorly pointed in lateral profile; mouth small and subterminal; eye large, situated on dorso-lateral part of head, closer to tip of snout than to posterior end of operculum; interorbital distance smaller than eye diameter; nostrils closer to anterior border of eye than to tip of snout (Ref. 129519). Dorsal fin with 3 unbranched and 9-10 branched rays, anal fin with 3 unbranched and 5 branched rays, 12-13 pectoral-fin rays, 9 pelvic-fin rays; dorsal-fin origin located anterior to midbody and slightly anterior to vertical through pelvic-fin insertion; distal profile of dorsal fin nearly straight; distal profile of pectoral fin slightly concave; third pectoral-fin ray longest, extending beyond pelvic-fin insertion, remaining rays gradually decreasing in length; third pelvic ray always longest; tip of pelvic fin passing beyond urogenital opening but clearly falling short, about three scales of anal-fin origin; adipose fin well developed, its origin along vertical through of last branched anal-fin ray; caudal fin bifurcated with equal-sized lobes or upper lobe larger than lower (Ref. 129519). Lateral line complete, straight and in mid-lateral position, from behind operculum to middle of caudal-fin base; lateral line scales smaller on predorsal area than below dorsal fin; three or five scales of lateral line extending on caudal fin and also smaller than scales below dorsal fin; scales on lateral line 49-55, scales between lateral line and dorsal-fin origin 5, scales between lateral line and pelvic-fin origin 4-5, predorsal scales 13-15, scales between anus and anal fin origin 7-9, scales between dorsal and adipose fin 14-17, circumpeduncular scales 16 (Ref. 129519).

Colouration: Living or freshly caught specimens characterized by yellowish to pale-brown overall ground colouration of head and body; dorsal surface of head and snout bright yellow from anterior portion of upper lip to posterior of supraoccipital spine; lateral surface of head with dark stripe running from tip of snout to anterior margin of eye; upper half of eye with dark grey iris and sometimes white on lower half; white-yellowish ring around pupil; ventral region of head white; metallic black spot on operculum; dorsal region of body brownish yellow; scales on dorsal region of body usually with dark brownish pigmentation along distal border resulting in overall reticulated colouration pattern; black stripe, about one scale wide, extending from posterior border of operculum to caudal-fin base; eight to 10 vertical blackis bars on flank, each covering two or three successive lateral line scales, extending up to two scales row above and up to four scales rows below lateral-line scales; number, position and shape of vertical bars varying from one side to the other, but difference between both sides never exceeding one bar; in general, two or three bars in front of dorsal fin, two under dorsal-fin base, three between dorsal and adipose fins, and last two on caudal peduncle of which one below adipose fin and one in-between posterior edge of adipose fin and anterior edge of caudal-fin base; anterior bars slightly longer than posterior ones; two last bars situated on caudal peduncle nearly as high as wide; last bar on caudal peduncle extending slightly posteriorly over base of medial caudal-fin rays; fins with transparent membranes; anal and pelvic fins with one transverse black band, widening anteriorly (Ref. 129519). In preserved specimens, overall colour of body yellowish to brownish with lighter coloured venter; bars on flank and bands on pelvic and anal fins become more evident and brown in freshly preserved specimens than in living or freshly caught specimens (Ref. 129519).