Distinguished from other members of the genus Pimelodus, except Pimelodus maculatus and Pimelodus mysteriosus by having dark brown blotches in the flanks. Differs from Pimelodus argenteus by the blotched color pattern; and from Pimelodus mysteriosus by having smaller maxillary barbel. Can be differentiated from Pimelodus maculatus by having supraoccipital process more robust, with base as broad as long (vs. longer than broad); anterior nostrils 25% of distance between the margin of snout to posterior nostrils (vs. 33%); small saws in the pectoral spine more developed and present in more than half of the anterior margin of spine (vs. small saws present in less than half of that margin); head covered with very thin skin, allowing the grooves in the bones surfaces conspicuous; 22-27 gill rakers in the first branchial arch (vs. 19-24); larger values of interorbital distance, mouth width and maxillary barbel length; and by having smaller base length of adipose-fin (Ref. 74927).