Such artificial fish exist only in a computer netherworld. The fish, displayed on a color monitor, swim together within a supercomputer's processors. Each emanates from an autonomous computer program nested within a larger program, which generates a simple underwater ecosystem. Artificial fish learn to control internal muscles to loco-mote hydrodynamically and exhibit a repertoire of realistic behaviors, relying on their perception of a dynamic habitat. Each fish explores its environment and searches for food.
Predators select, chase, and consume prey until satiated.
Other fish forage for plankton and engage in mating rituals. An intention generator helps the fish to avoid collisions, evade predators, eat, mate, school, or wander. The researchers program each fish's affinity for darkness, coolness, and schooling, plus its level of hunger, fear, or desire to mate. Undulating in a lifelike way, each fish's body is based on a computer model of 91 interacting springs in place of muscles. Hydrodynamic control systems sense virtual water and adjust simulated fins to send a fish where it wants to go.