Golden shiner (Notemigonus crysoleucas) and rudd (Scardinius erythrophthalmus) have been hybridized in a laboratory experiment and a hatchery setting but have not been reported in wild populations. Here we report the presence of golden shiner × rudd hybrids in the wild in Lake San Isabel, Colorado, where both parental species maintain reproducing populations. The hybrid was identified based on intermediate squamation of the keel (cultrate abdomen), where a small fleshy ridge was present at the posterior edge of the keel adjacent to the vent. In contrast, the keel of the golden shiner lacks squamation entirely while the keel of the rudd is completely covered by scales.