Diagnosis: Luciobarbus rabatensis differs from other species of Luciobarbus by the following combination of characters: number of scales on lateral line 45-50; number of scales above lateral line 8.5-10.5; number of scales below lateral line 6.5-7.5; insertion of dorsal and ventral fins is in the same vertical plane; last single fin ray is ossified, with deep denticulations along its length; denticulations at mid-height of the ray are equal to or longer than ray width; in adult specimens, the inferior lip is retracted revealing the dentary; the ethmoid bone is wider than its length; the maxilla showed a large palatine process; vertebrae 41-42; and gill rakers 12-14 (Ref. 107580).

Description: It is a medium-sized species that rarely reaches 500 mm; the body is slightly more elongated in comparison with Luciobarbus rifensis and L. maghrebensis with maximum body depth ranging from 24.4-28.5% of standard length; the head is large relative to the body, similar to other Luciobarbus species, with head length 23.5-26.8% of standard length (Ref. 107580). The preorbital distance is short and the proportion with respect to head length is 29.2-40.5%; the circumorbital bones are narrow; the barbels are similar in size to those of Luciobarbus maghrebensis and L. rifensis, but, due to a shorter snout, the first barbel usually reaches the anterior edge of the eye; the second barbel usually extends to the posterior edge of the eye, but does not reach the preopercle; the anterior barbel is 22.1-26.3% of head length and the second 22.3-32.8% of head length; the lips of adult specimens are usually retracted, and the dentary bone is visible; the lacrimal bone has a short and high manubrium; the iris is yellow pigmented at the superior border (Ref. 107580). The dorsal fin is placed posteriorly on the body with a predorsal length of 50.9-56.3% of standard length; dorsal fin with 4 unbranched and 8 branched rays; the profile of the dorsal fin is concave with the last single ray ossified with pronounced denticulation; the pectoral and ventral fins are longer in males, and the anal fin is longer in females; anal fin with 3 unbranched rays and 5 branched rays; pectoral fin with 1 unbranched ray and 15-16 branched rays; pelvic fin with 1 unbranched ray and 8 branched rays; the caudal fin is long, with a length of 20.4-24.2% of standard length (Ref. 107580). The caudal peduncle is slightly more elongated than in Luciobarbus maghrebensis and L. rifensis, with a height from 34.7-38% of standard length; the height of the caudal peduncle is 1.4-1.7 times the anal peduncle length (Ref. 107580). Pharyngeal teeh in adults 4.3.2-4.3.2 (Ref. 107580). The skull is long and narrow with the ethmoid bone wider than its length; the lacrimal bone is short; the basioccipital bone has a wide pentagonal plate; the palatine process of the maxilla is more conspicuous and the pharyngeal bone is narrow (Ref. 107580).

Colouration: The colour is slightly yellow, brownish in the dorsal region and more silver in the ventral area (Ref. 107580).