The whale shark, Rhincodon typus, is a slow moving filter feeding shark that is the largest living fish species. It can grow up to 12.2 m (40 ft) in length and can weigh up to 13.6 tonnes (15 short tons). The shark is found in tropical and warm oceans and lives in the open sea and can live for about 70 years. The Boar Fish commenced to feed on frozen brine shrimp after being initially encouraged with live daphnia. It seemed initially to feed better when the circulatory water pump (powerhead) was turned. The Monterey Bay Aquarium has come up with a guide to buying and eating fish from sustainable sources. Almost three-forths of the world's surface is covered in water. This water is home to over 20,000 different species of fish. Every night, certain species of parrot fish envelope themselves in a transparent cocoon made of mucous secreted from an organ on their head. The earliest fossils of fish date back over 400 million years. It's hard to decide which of the colorful parrot fish's many unique characteristics is most remarkable.