About 1800 years ago, a volcano in northern Nicaragua exploded. The crater formed by the eruption slowly filled like a rain barrel. Eventually the water rose high enough to warrant the title of lake. Today it is called Lake Apoyeque. Although Lake Apoyeque is over 300 feet deep, the rains have a long way to before they reach its brim. Lake Apoyeque remains ringed by volcanic cliffs towering as high as 1200 feet. And yet, despite its young age and its remote location, it is filled with fish.

For thirty years, Axel Meyer, an evolutionary biologist now at the University of Konstanz in Germany, has journeyed to Lake Apoyeque and other lakes of Nicaragua to study the evolution of their fish. He