Monitoring and analysis fish population is one of the ecological observation which is the most important aspect to monitor the environmental condition. However, it is difficult to sustain a long-term and real-time observation on fish population, mainly as a result of the inaccessibility of the marine environment. In this project, an underwater surveillance system is developed which is equipped with an underwater surveillance camera and wireless data transmitter that will send the data from underwater to the computer. The data from the system is than being processed in the computer using image processing in MATLAB software to detect and track the fish populations. Finally, the visualization of data and analysis is made from the system.