THE life cycles of various species of fish include long range migrations for feeding and spawning purposes. Long stretches of these migratory routes are often crossed without food intake so that efficient use of the store of internal energy is essential to survival. Many such migratory species have produced various adaptations for efficient swimming such as streamlining and carangiform1 body movements. Schooling, which is also common among long distance swimming species2, has been shown to contribute to the locomotory performance3. Here I show that regulating the swimming speed can increase the performance and efficiency of motion by appreciable amounts.