This species, a member of the orthodus species-group of Astyanax, differs from other members of the group by the following characters: differs from villwocki, superbus, gandhiae, bopiensi, boliviensis, yariguies by the absence of a dark stripe on the sides of the body (vs. dark lateral stripe present or anterior prolongation of the caudal peduncle spot extending anteriorly over the silvery lateral stripe); differs from A. orthodus in having the caudal peduncle spot extending onto the ventral and dorsal margins of the caudal peduncle, covering 4-6 horizontal scale rows (vs. covering 2-4 horizontal scale rows on the caudal peduncle) and in having an unpigmented band across the anal-fin rays in both sexes (vs.pigmentation uniform on analfin rays); differs from A. moorii in body depth > 39% SL (vs. < 39% SL), the dorsal-pectoral fin distance > 40.5% SL (vs. < 40.5% SL), maxilla length < 33.5% HL (vs. > 33.5% SH), upper jaw length < 32% HL (vs. > 47% SH) and by the number of lateral-line scales 36-41 (vs. 44-50) (Ref. 119406).