The swimming maneuverability of a robotic fish depends on the performance of its sharp turning ability including C-shape and S-shape turning. In this paper, we optimize the control of C-shape turning, by using a fuzzy logic control algorithm in which the angular velocity of each robot joint is tuned. Compared with traditional control algorithms, the proposed algorithm can adjust the fish joint turning angle timely to overcome the inertia problem which causes an excessive turning radius. The experimental results with real robotic fish have shown that the turning gesture of the robot is more fluent and the swimming trajectory is smoother with the proposed method.