Chinese Paddlefish (left) and Chinese Sturgeon (right).

The Chinese Paddlefish (Psephurus gladius) is a near-extinct species of freshwater Paddlefish, from the family Polyodontidae and the genus Psephurus. It lives only in the Yangtze River, Japan and is easily one of the rarest fish in the world. Little research on this fish concludes that it was once capable of growing over 3 meters long and weighing over 550 pounds. This fish uses filter feeding, eating only tiny organisms. Different research teams have gone on searches to see if the fish was still thriving, but all have brought back 0 results.