The fish wander about eating the algae and reproducing. Once a fish appears, it doesn't take long for the entire world to be covered with them. Sharks wander around the torus of Wator, eating fish and reproducing. If a shark doesn't find a fish to eat within a specific period of time, it starves to death. Sharks cannot reproduce unless they eat.
Sharks can mutate too.
Rarely, the time that a shark can survive without eating is randomly increased or decreased. The color of a shark depends upon this time factor according to the following table. The patterns that these tiny creatures form on the Wator map can be hypnotizing. They are quite pretty. But more than that, they tell a picture of a violent and precarious existence.