Diagnosis: Pseudobarbus afer differs from P. burchelli, P. burgi, P. skeltoni and P. verloreni by the possession of a single pair of oral barbels (Ref. 114782). The possession of fewer and larger scales separates P. afer, which has 29-35 scales along the lateral line, from P. quathlambae and P. asper, with respectively more than 60 and more than 35 scales along the lateral line (Ref. 114782). Lack of a mid-dorsal stripe and a relatively deeper head and body profile separates P. afer from the more slender bodied P. tenuis, head depth being 66.5-78.2% of head length vs. 61.1-71.2% and body depth being 22.5-31.6% of standard length vs. 18.8-26.8% (Ref. 114782). Lack of prominent black spots and patches on the body distinguishes P. afer from P. phlegethon (Ref. 114782). Pseudobarbus afer most closely resembles P. senticeps, P. swartzi and P. asper; barbel length and the number of scale rows along the lateral line separates P. afer from these three species; short barbels which do not reach the vertical through the posterior margin of the eye and a higher number of lateral line scales, 29-35, distinguishes P. afer from P. senticeps whose barbels reach or surpass the vertical through posterior edge of eye and has fewer and larger scales along lateral line, 25-30, and around caudal peduncle, 10-12; it further differs from P. senticeps by lack of a blotch of pigment at the base of the caudal fin, while the lateral stripe in P. senticeps terminates in a triangular blotch at the base of the caudal fin (Ref. 114782). Pseudobarbus afer differs from P. swartzi by possession of fewer scale rows along the lateral line, 29-35 vs. 34-37, and fewer scales around the caudal peduncle, 12-16 vs. 13-17; it has a distinct mesh-like pigmentation pattern below the lateral line which further separates this species from P. swartzi which lacks discernible pigmentation pattern on the latero-ventral scales (Ref. 114782). Pseudobarbus afer is separated from P. asper by the possession of fewer and larger scales, lateral line scale series 29-35 vs. 35-45 and caudal peduncle scale rows 12-16 vs. 16-22 (Ref. 114782).

Description: Body fusiform, more or less laterally compressed, with dorsal profile generally more convex than ventral profile; body deepest around the anterior bases of the dorsal and pelvic fins; caudal peduncle length is almost twice its depth (Ref. 114782). Head length sub-equal to body depth, snout slightly blunt, mouth sub-terminal and sickle shaped, with a single pair of simple short maxillary barbels; barbel length shorter than orbit diameter, barbels do not surpass the vertical through posterior margin of pupil; eyes moderately large, located dorsolaterally, closer to tip of snout than to the posterior margin of gill cover, orbit diameter shorter than snout length (Ref. 114782). Scales: 29-35 scale rows along the lateral line to end of hypural plate, 1-2 more scales to base of caudal fin; 4-6 scale rows between lateral line and anterior base of dorsal fin; 3-5 scale rows between lateral line and pelvic fin origin; 3-5 scale rows between lateral line and anal fin origin; 14-16 predorsal scale rows; 12-16 circumpeduncular scales; triangular naked patch between the gill covers and anterior base of pectoral fins, ventral scales between pectoral fin origin and pelvic fin origin reduced and embedded; axillary scales of pelvic fin not prominent or elongate; scales between posterior edge of head and dorsal fin origin embedded and smaller than flank scales (Ref. 114782). Dorsal fin situated almost in the centre of the body, origin slightly behind vertical through origin of pelvic fin, with 3-4 unbranched rays and 6-7 branched rays, distal margin straight to slightly concave, tip of depressed dorsal fin reaches within 1-2 scales to vertical through posterior base of anal fin; pectoral fins fan-shaped, larger in males than females, with 14-17 rays, often reaches and surpasses base of pelvic fin in males, reaches 2 scales to base of pelvic fin in females; pelvic fin with 8-9 rays, origin slightly in front of dorsal fin origin, tip of depressed pelvic fin does not reach anterior origin of anal fin, except in mature males; anal fin with 3 simple rays and 5-6 branched rays, distal margin almost straight to slightly convex, origin closer to anterior base of pelvic fin than caudal fin base; caudal fin is obtusely forked, with a mode of 10+9 principal rays (Ref. 114782). Total vertebrae including Weberian apparatus 36-39, predorsal vertebrae including Weberian apparatus 11-13, precaudal vertebrae including Weberian apparatus 18-20, caudal vertebrae 17-19 (Ref. 114782).

Colouration: Dorsum grey-black, sides and belly silvery white, base of fins bright red in adults; vague dark mid-lateral band from behind the head to the base of the caudal fin (Ref. 114782). The bright red pigmentation on base of fins and silvery colouration fades in preservative; dorsum and flanks above lateral line dark greyish; belly off-white to yellow in most specimens; band of pigment around centre of scales, basal segment of exposed area of scales without pigment, leaving a lighter band along distal edges of scales, producing a mesh or net-like pattern which is more pronounced on dorso-lateral scales (Ref. 114782).