Pirarucú is located within the Mamirauá Reserve, about 600 km west of Manaus, a complex of lakes and channels between the Solimões River and Japura River. Mamirauá was the first Sustainable Development Reserve in Brazil, legislated by the Government of Amazonas in 1996, and remains the largest arapaima reserve in the world. Arapaima (Pirarucu) are hard fighting, tarpon-like fish that can grow to over 400 pounds. Their jumps and though battles make them an amazing sport fish.