Diagnosis: Marcusenius kaninginii belongs to the group of Marcusenius species with eight large circumpeduncular scales (Ref. 113607). Within this group it can be distinguished from M. dundoensis, M. fuscus and M. sanagaensis by its lower number of lateral line scales, 43-47 vs. 49-61; it differs from M. ghesquierei and M. kutuensis by having fewer dorsal-fin rays, 18-23 vs. 27-34; and from M. schilthuisiae by fewer anal-fin rays, 27-30 vs. 32-35 (Ref. 113607). It is distinguished from M. intermedius by a higher number of lateral line scales, 43-47 vs. 38-43, and a higher total vertebrae number, 42-44 vs. 40-41; furthermore, it can be distinguished from M. intermedius by the terminal mouth position and the rounded shape of the snout vs. mouth sub-terminal and the snout pointed; it is distinguished from M. moorii by the blackish longitudinal band along the lateral line; the shallower body at the anterior base of the anal-fin depth, 25.0-28.4% of standard length vs. 28.1-33.5; the shorter pectoral fin, 15.5-19.1% of standard length vs. 17.7-22.8; and the deeper caudal peduncle, 39-57% of its length vs. 27-42 (Ref. 113607).

Description: Body elongate; head profile straight and a little convex at head tip (Ref. 113607). Mouth terminal; chin with a small sub-mental swelling; upper jaw with 5 and lower jaw with 5-6 bicuspid teeth; one single row of teeth in both upper and lower jaws; in upper jaw 3 median teeth placed in a straight line, while 2 outer a little backwards; in lower jaw, teeth formed a curved line; eye small, situated in anterior half of head, somewhat nearer to dorsal margin of head; upper and lower nostrils not in vertical plane, upper one more anteriorly than lower one (Ref. 113607). Predorsal distance longer than preanal distance; dorsal fin shorter than anal fin, originating slightly behind origin of anal fin; ration dorsal-fin/anal-fin length 0.6-0.9; body depth at middle of body equal to body depth at level of anal-fin insertion; distance between pectoral and anal fins slightly shorter than pre-pelvic distance (Ref. 113607). Scales on the body just behind the head small, becoming larger more posteriorly (Ref. 113607).

Colouration: Live specimens dark-brown in overall colour; in addition, a transversal black bar between anterior parts of anal and dorsal fins covering 3-4 consecutive scales at level of lateral line, and extending on to anterior parts of dorsal and anal fins; further, a black mid-longitudinal band from posterior edge of head near operculum to black transversal bar; caudal peduncle dark (Ref. 113607). Often two additional vague black markings on fresh as well as on recently preserved specimens: a first one near anterior origin of lateral line; a second one towards posterior end of caudal peduncle (Ref. 113607). After preservation, dark background colour of body fading; as a result, black mid-longitudinal band standing out much more clearly (Ref. 113607).