Crowd behaviors on cyber underwater environment are often produced in entertainment contents, such as films and games. It is easy for us to come in contact with the scenes appearing a lot of characters as digital films and animation works are increased gradually, owing to developing of computer graphics. Though the processing a scene of crowd and the behavior system of crowd, related to the processing techniques of crowd behavior in cyber space, have been implemented so far, the research for developing the natural crowd behavior simulator can not be still satisfying. In this paper, we designed a realistic and efficient Fish Schooling Behavior Simulator for the contents production of cyber underwater environment, which showed each type of fish behavior in cyber underwater smartly, and which generated the animating the behavior automatically, reducing the time and cost.