Distinguished from all species of Leporinus except, L.amblyrhynchus, L. conirostris, L. desmotes , L. despaxi, L. elongatus , L. jatuncochi , L.macrocephalus, L. muyscorum, L. obtusidens, L. reinhardti, L. trifasciatus and L. wolfei, by possessing three teeth on premaxilla and dentary (vs. tooth formulae 3/4, 4/4 or 4/3). Can be separated from from L. amblyrhynchus, L. conirostris, L. desmotes, L. despaxi, L. jatuncochi, L. macrocephalus, L. muyscorum, L. reinhardti, L. trifasciatus, and L. wolfei by having three dark rounded blotches on the body and dark transverse bars usually persistent in large specimens (vs. body with a dark midlateral stripe in L. amblyrhynchus, and L. despaxi; transverse dark bands in L. desmotes and L. jatuncochi; body pale except for a single dark blotch on caudal peduncle in L. conirostris; first blotch, below the dorsal fin, transversely elongated in L. macrocephalus, L. trifasciatus and L. wolfei; transverse bars faded in large specimens of L. muyscorum; and blotch on the caudal peduncle longitudinally elongated, not rounded, sometimes making contact with the second blotch in L. reinhardti). Differs from L. elongatus by having 16 circumpeduncular scale rows (vs.12); from very similar species L. obtusidens by having 39 to 40, exceptionally 41, perforated scales on the lateral line (vs. 41 to 43, rarely 44). Individuals of Leporinus piavussu particularly discriminate from individuals of L. piavussu from the upper Rio Paraná basin by having a terminal mouth, its cleft above the horizontal through the ventral orbital margin (vs. mouth directed somewhat or entirely downward, its cleft at the horizontal through the ventral orbital margin or below) (Ref. 93038).