Astyanax pelecus is a species of characid fish from Brazil. It can be distinguished from its cogenerate species by: its body depth (26.7-34.8% of its standard length); its short and pointed snout smaller than the orbital diameter; and a reduced number of branched anal fin rays. A. pelecus also differs from members of its genus by its characteristic color pattern. It possesses a single humeral spot that is constricted to the region above the lateral line; at the same time it shows a conspicuous midlateral body stripe from opercle to the caudal fin base, an autapomorphy of this precise species. Most other Astyanax species have a humeral spot that is vertically or horizontally elongate and have the midlateral stripe becoming faint near that humeral spot. The species name is derived from the G