This research focuses on the application of the optical flow method for target identification and tracking of largemouth bass in underwater environments. The optical flow field, representing pixel movement on a two-dimensional plane, is utilized to analyze grayscale variations in image sequences. The study employs the basic variational optical flow model and introduces the Horn-Schunck (HS) algorithm to address challenges such as the aperture problem. Additionally, the paper explores camera selection and calibration, emphasizing the importance of accurate calibration parameters for binocular vision systems. A domestication experiment is designed for California black bass, incorporating sound stimuli and optical flow-based motion tracking. The study concludes with an evaluation of fish domestication effects using motion trajectory and speed analysis.