This research presents the design and development of a bio-inspired underwater robot that utilizes a gear-based flapping mechanism to emulate the efficient propulsion of aquatic creatures. By mimicking the motion of fish, the robot aims to achieve agile maneuverability and high propulsive efficiency in underwater environments. The core components of the robot include a streamlined hydrodynamic hull, a gear-based flapping mechanism, a robust propulsion system, a comprehensive sensor suite, and a reliable communication system. The gear-based mechanism, specifically designed to convert rotational motion into precise flapping motion, is a critical element in achieving the desired propulsion performance. The robot is equipped with a variety of sensors, including depth sensors, hydrophones, cameras, and inertial measurement units, to perceive its surroundings and make informed decisions. Advanced control algorithms are employed to coordinate the flapping motion, maintain stability, and execute complex maneuvers. Through rigorous simulations and experimental testing, the performance of the robot is evaluated in terms of speed, maneuverability, and energy efficiency. The numerical analysis shows maximum coefficient of lift 0.72 for St = 0.32 with inlet velocity of 1.773 m/s. The results demonstrate the potential of bio-inspired designs for developing innovative underwater robots capable of exploring challenging environments and performing critical tasks.