Environmental flows delivered to rescue native fish from drying floodplain wetlands also facilitate the dispersal of common carp (Cyprinus carpio). Carp responses to these flows are difficult to observe in structurally complex, largely inaccessible systems using conventional tracking approaches. We first validated UAV-based radio telemetry in a floodplain wetland, achieving mean spatial error of 13.1 ± 6.5 m, the first such validation for tracking fish. We then applied it in the regulated lower Murrumbidgee, where targeted flows in summer 2024/2025 reconnected an ephemeral lake to the main river channel so entrapped fish could escape. We radio-tagged 26 common carp as they exited the lake and tracked them daily with handheld and drone-mounted receivers. Seventeen carp dispersed up to 25 km across the floodplain and never returned, while eight came back to the lake. Movement peaked 22 days after connection, then declined as falling water levels rendered structures impassable and fragmented the wetland into isolated pools. Flows delivered for native fish also create opportunity for carp, making the timing of flows and operation of structures a key lever for managing that trade-off in regulated floodplains.