Fig. 1. Schematic diagram of the behavioral testing apparatus used to elicit and analyze goldfish C-starts. Light is projected from above and fish images are captured from below the tank by both a video camera and a matrix camera. Goldfish are stimulated with a vibratory stimulus created by lifting the whole tank with a solenoid. The computer simultaneously triggers the solenoid and the matrix camera, which starts saving silhouettes at a rate of 500 silhouettes s^-1 (i.e. every 2 ms). These fish silhouettes are stored in the expanded memory of a controller and then loaded onto the computer hard drive for analysis.