Barbus karunensis is distinguished from other members of Barbus lacerta group by having a well-developed middle pad of the lower lip (vs. poorly developed or absent). It differs from B. cyri by having a thin upper lip (upper lip width 4-6 %HL vs. 7-9 % HL), and from B. lacerta by having a shorter anal fin; the tip of the anal fin is not reaching or reaching to about the middle of the distance between the base of the last anal-fin ray and the lower caudal-fin origin when pressed to the body (vs. reaching beyond middle, often to caudal-fin base); scale rows between the tip of the anal fin and the base of the caudal fin 5-9, mode 6 (vs. 0-3, mode 2). It can be differentiated from B. miliaris by having 59-66+2-4 (mode 61) scales in the lateral line (vs. 69-87+3-5); 26-29 (mode 26) circumpeduncular scales (vs. 28-35); maxillary barbels not reaching the middle of the eye (vs. reaching beyond), and a longer snout (eye diameter 2.7-3.5 times in snout length vs. 2.3-2.6 or eye diameter 27-35% snout length vs. 23-26%) (Ref. 115584).