In this paper, I explain a school behavior model, which was constructed by Aoki, Huth, and Wissel, used to describe the motion of schools of fish. Schools of fish are characterized by strong cohesion and high parallel orientation without using a leader. In this model, each fish can exhibit one of four basic behavior patterns -- repulsion, parallel orientation, attraction, and search -- based on its proximity to a neighbor fish. I modified the model in how the fish mixed the influence of its neighbors; the fish takes a weighted average of the influences of its neighbors. I constructed a computer simulation model using robots to test this model, and my data has shown that the model is quite successful in simulating the characteristics of a school of fish. The ultimate goal of this research isto apply the school behavior model to algorithms for robot formations.