Diagnosis: adipose fin always present; anterior two nostrils closer to each other or almost at same distance from each other than posterior ones; inner mandibular barbel very slender, rudimentary or absent (sometimes only present on one side of head), if present never reaching beyond anterior eye border; eyes very small (especially in large specimens: negative allometry), 12.0-23.3% HL; snout reaching beyond lower jaw; inner side of pectoral spine feebly serrated; pelvic fin base slightly advanced in comparison with other related species, situated at same level as origin of dorsal fin base (Ref. 43912).

Description: 52-61 branched anal rays; 48-49 non- fused vertebrae; 8-9 branchiostegal rays on one side of head; caudal peduncle longer than deep (Ref. 43912). Variation of barbel length: nasal barbel sometimes very short, not even reaching to anterior eye border, at maximum reaching to just beyond posterior eye border; maxillary barbel at least reaching to anterior border of opercle and at maximum reaching to posterior border of opercle; outer mandibular barbel at least reaching to halfway between eye and opercle and at maximum to anterior border of opercle; inner mandibular barbels rudimentary (Ref. 43912). In some specimens anterior soft rays of pectoral, dorsal and anal fins slightly elongated or filamentous, these filaments much shorter than in related species S. banguelensis; pectoral fin sometimes reaching beyond origin of anal fin (Ref. 43912). Schilbe congensis belongs to the group of silvery uniformly coloured species with a rather small inferior mouth, the snout reaching beyond the lower jaw and the anterior nostrils closer to each other than are the posterior ones, which is also the case in S. grenfelli, S. mystus, S. banguelensis and S. nyongensis; however, the strikingly small eyes and the rudimentary inner mandibular barbels in S. congensis permit a rather easy distinction of this species (Ref. 43912).

Coloration: in alcohol: head and back brownish, sides pale and silvery; belly also pale; large dark blotch visible where swim-bladder lies close below the skin; fins more or less colourless; Copley (1952) mentioned a dark longitudinal streak in some juvenile specimens but it is not certain that these juveniles really belonged to S. congensis (Ref. 43912).