Diagnosis: Garra duobarbis is unique among the African Garra species in possessing a single (maxillary) pair of barbels (Ref. 58532).

Description: Garra duobarbis is a robust species, and relatively deep-bodied; greatest body depth located well anterior to dorsal-fin origin, at level of pectoral-fin tips (Ref. 58532). Head depressed and flattened; snout short and bluntly rounded, with no tubercles; eyes positioned a little anterior on head (Ref. 58532). Dorsal head profile rises smoothly over snout and head; dorsal body profile steeply convex to dorsal-fin origin, often with a sharp demarcation between dorsal head profile and dorsal body profile (Ref. 58532). Disc extremely weakly developed and inconspicuous without either free posterior edge or distinct lateral margins; rostral cap well developed with smooth ventral margin extended ventrally over upper jaw (Ref. 58532). Rostral barbels absent; single pair of maxillary barbels, relatively long and conspicuous (Ref. 58532). Between 34 and 36 scales along lateral line; 4.5 scales from lateral line to origin of pelvic fin; 5.5 scales from lateral line to origin of dorsal fin; no predorsal scales anterior to dorsal fin, chest and belly asquamate, postpelvic region scaled (Ref. 58532). Dorsal fin with iv,7 rays, inserted just anterior to pelvic fin, with rounded tip, second branched ray longest; anal fin with iv,5 rays, with short subacuminate tip; pectoral fin with iv,12 rays, rounded and paddle-shaped, its length 12.9-21.4% of standard length (Ref. 58532). Predorsal length 50.6-54.0% of standard length (Ref. 58532). Vent located relatively close to anal fin (Ref. 58532).

Colouration: Base body colour pale creamy brown, slightly darker dorsally, pale cream below lateral line and ventrally (Ref. 58532). Snout, dorsum of head and anterior opercle brownish-grey; lips, cheek, gular region and branchiostegal membranes pale creamy yellow; posterior border of opercle also pale cream; pale coloration extends postero-dorsally to eye (Ref. 58532). Dorsal-fin membrane pale cream distally, broad submarginal band of black pigment in membrane between rays, and pale cream proximally; either 5 or 6 small spots between rays in basal membrane of dorsal fin; anal fin cream in smaller specimens, with broad submarginal band of black pigment in larger specimens; distinct black spot in fin membrane at base of caudal fin; medial caudal-fin rays dark brown and membranes pale cream, whole fin with a pale distal margin; pelvic and pectoral fins pale creamy brown with pale leading edges (Ref. 58532).