James Prosek wrote his first book — Trout: An Illustrated History — at age 19 for the publisher Alfred A. Knopf. It featured 70 of his paintings of the North American fish. Since then, he’s written for National Geographic and The New York Times Magazine and co-founded, with Patagonia’s Yvon Chouinard, a conservation organization called World Trout that works to preserve coldwater habitats. Prosek recently published a book titled Eels: An Exploration, from New Zealand to the Sargasso or the World’s Most Amazing and Mysterious Fish and is working on another book about Atlantic fishes that are going extinct. He is the subject of the short documentary Picture the Leviathan.