Astyanax ocotal is distinguished from other congeners in the region by the following characters: head length, 29-33% SL (vs. 22- 28% in A. angustifrons and A. finitimus, to 30% in A. aeneus); anal-fin base length, 26% SL or less (vs. 26% or more in A. aeneus and A. finitimus); lower-limb gill rakers in first arch, 15-16 (vs. 14 or fewer in A. angustifrons and A. finitimus); urohyal, ventral apex closer to caudal end (vs. about equidistant between rostral and caudal ends in A. finitimus); epibranchial III, distal segment straight (vs. curved in A. finitimus); preopercle with divergent canals at angle (vs. canals parallel in A. angustifrons); coracoid with 4-5 interdigitations in suture to cleithrum (vs. 2-3 in A. angustifrons) (Ref. 118583).