Azygia aphredoderi n. sp. is described from the stomach of the pirate perch Aphredoderus sayanus (Aphredoderidae) collected from the Menard Creek Corridor Unit of the Big Thicket National Preserve in Texas, U.S.A. The new species is similar to Azygia angusticauda in that the ventral sucker and gonads are placed posteriorly, characteristics that allow both species to be distinguished from all others in North America. Members of the new species are characterized by a ventral sucker that is larger than the oral sucker, small body size (<2 mm), small length-to-width ratio, and a forebody-to-hindbody ratio of nearly 1.0, all of which allow them to be distinguished from A. angusticauda.