This species can be diagnosed from all other congeners by a conspicuously reduction on posterior laminar expansion of infraorbital 2, almost absent in some specimens (vs. infraorbital 2 with moderate- or well-developed posterior laminar expansion). This can be distinguished from other species of Corydoras, except C. longipinnis and C. tukano, by exhibiting uncommon sexual dimorphic condition, with the conspicuous elongation of the first and second branched dorsal-fin rays in males surpassing dorsal-fin spine distal tip, with size similar to the total length of the spine (vs. dorsal fin not sexually dimorphic with respect to its length; or elongation of dorsal-fin elements (when present) not associated with sexual dimorphism; or dorsal fin, if sexually dimorphic, with first and second dorsal-fin branched rays slightly surpassing dorsal-spine distal tip). This can be differentiated from C. longipinnis and C. tukano by having four to six irregular black or brownish blotches on the midline of the flank (vs. midline of the flank with three large black rounded blotches in C. longipinnis; two very large black rounded blotches in C. tukano); and from C. longipinnis by having the mesethmoid not visible, entirely covered by a thick layer of skin (vs. visible, posterior portion of mesethmoid covered by a very thin epidermal layer) (Ref. 95506).