Fishes present a unique opportunity to investigate hypotheses related to multimodal communication. Conspecific social interactions in fish are characterized by visual aggressive and courtship displays that involve directed movements of the body and fins, resulting in the local displacement of the surrounding water. Because fish are able to perceive near-field hydrodynamic features of the physical environment via the lateral line system, these body-generated hydrodynamic flows have the potential to function as mechanosensory signals that assist receivers in making appropriate behavioral decisions. Here, we tested the hypothesis that mechanosensory signals generated by male fish during courtship influence female mate choice decisions. We manipulated the ability of female fathead minnows, Pimephales promelas, to detect changes in water flow via the lateral line system and conducted choice tests to determine whether females with and without access to mechanosensory information differed in patterns of mate discrimination. In dual-choice assays, female minnows without access to mechanosensory information from courting males showed reduced mate discrimination compared to control females, and reduced reliance on male courtship as a criterion of choice. These data add new insight into the role of body-generated hydrodynamic flows as social signals and extend our limited understanding of the role of the lateral line system as a channel of intraspecific communication.