Dario huli is distinguished from all congeners, except D. urops, by having a conspicuous black blotch on the caudal-fin base and the anterior dorsal-fin lappets in males not being produced beyond the fin spines. It can be diagnosed from D. urops by having the following characters: horizontal suborbital stripe absent (vs. suborbital stripe present); a series of up to 8 black bars on the body (vs. 2-3 black bars restricted to the caudal peduncle); an oval caudal-fin blotch with a lighter bar in front of it, sometimes inconspicuous (vs. a round blotch with a curved, halo-like lighter area); 25 scales in a lateral row (vs. 28); 13+13=26 vertebrae (vs. 14+14-15=28-29); 3-5 tubed lateral-line scales (vs. tubed lateral-line scales completely absent); and teeth on hypobranchial 3 (vs. absence of teeth) (Ref. 98908).