Fishers in northern Thailand netted this huge catfish in the Mekong River on May 1. Nearly nine feet long (2.7 meters) and as big as a grizzly bear, the behemoth tipped the scales at 646 pounds (293 kilograms). Experts say the fish, which belongs to the species known as the Mekong giant catfish, may be the largest freshwater fish ever recorded. >> Natgeo.