This paper presents the findings of our research work to develop bio-inspired techniques for robotic fish navigation based on flow sensing and efficient cum optimized propulsion with a tractable mechanism inspired by fish. We describe the outcomes of simulation for stream flow sensing to choose angle of attack (Rheotaxis) and tail fin based propulsion investigations using SOLEIL with respect to salmon and zebra fish models. To detect difference in pressure on either side we have used Bayesian estimation of flow speed and orientation (direction) by ingesting pressure measurements into 2D & 3D potential flow model. Subsequently based on flow and pressure we have formulated suitable propulsion system to counter up and down streams.