Locks and dams are possible management points to block the spread of invasive Asian carps in the United States. Infusion of carbon dioxide (CO2) into water is one deterrent strategy being considered at navigational structures to reduce upstream fish passage that would not directly interfere with lock and dam operations. The goal of this study was to determine the efficacy of CO2 as a behavioral deterrent to free-swimming fishes. Telemetered bighead carp (Hypophthalmichthys nobilis) and grass carp (Ctenopharyngodon idella) were monitored within a U-shaped pond (30.5 m long x 13.7 m wide x 1 m deep) using a two-dimensional acoustic telemetry array. Gaseous CO2 was administered to one-half of the pond at 30, 75, or 150 L CO2/min while a comparable stimulus of atmospheric air without CO2 was simultaneously applied to the opposite side. Fish positions throughout nine independent trials were used to quantify and compare the spatial occupancy, movement patterns, and CO2 plume interaction of fish during CO2 treatment relative to normal swimming before treatment. See related manuscript for additional details on experimental methods.