Diagnosis: 31-35 (Ref. 80290) or 33-35 (Ref. 2880, 81279) lateral line scales. Fronto-parietal fontanel narrow, but always present, even in adults; 6.5 scales between lateral line and dorsal fin; 19-21 anal fin branched rays; 12-15 gill rakers on lower limb of first gill arch; 6 teeth in outer premaxillary row; no humeral spot (Ref. 2880, 80290, 81279). Head length/snout length 3.4-4.0; 11-11.5 predorsal scales (Ref. 80290).

Description: dorsal-fin origin at about same lever of pelvic-fin insertions; anal fin with 3 branched and 19-21 unbranched rays; jaws equal, 6 outer premaxillary teeth aligned in single row; dentition rather peculiar, since none of the teeth in second row are molariform and those which are excavated are much less so than in other Alestes and Brycinus species; sexual dimorphism affecting anal-fin shape in adult males, which also have the first rays of dorsal and pelvic fin filamentous, dorsal filament extending beyond adipose fin when pressed to body (Ref. 2880, 80290, 81279).

Coloration: very similar to B. longipinnis, with which it can be confused, but the latter species has lower number of scale rows above lateral line; precaudal blotch well-developed and extending to the hind margin of caudal fork; no humeral spot (Ref. 2880, 80290, 81279).