Piscivory in age-0 smallmouth bass (Micropterus dolomieu) on native species is documented widely; however, few studies report size of prey. On 16 July 2008, we collected a smallmouth bass (65 mm in total length) with a bigscale logperch (Percina macrolepida; 44 mm in total length) in its gastrointestinal tract, from the Pecos River near Puerto de Luna, Guadalupe County, New Mexico. Smallmouth bass are nonnative in New Mexico. Bigscale logperch are listed as threatened in New Mexico, and the ability of age-0 smallmouth bass to take bigscale logperch at least 68% of their total length as prey should raise concerns about stocking smallmouth bass in areas where bigscale logperch and other native species occur.