Robotic fish with multiple torque reaction engines

A robotic fish comprises a plurality of torque reaction engines, wherein each torque reaction engine in the plurality of torque reaction engines comprises a driveshaft, an inertial mass mounted around the driveshaft, and a motor, wherein the motor is to generate a torque on the driveshaft by changing an acceleration vector of the inertial mass relative to the driveshaft, and a fish body, wherein the torque on the driveshaft from changing the acceleration vector of the inertial mass relative to the driveshaft is to cause a wave to propagate across the fish body, including through a flexible wing, wherein the wave is to accelerate thrust fluid and propel the robotic fish.