The Mekong giant catfish ("Pangasianodon gigas") is a rare species of catfish. It is a part of the shark catfish family. It is one of the biggest species of freshwater catfish. It is endemic to the lower half of the Mekong River. Because of overfishing and habitat loss, the fish is now critically endangered. Sometimes, Mekong giant catfish are raised in aquaculture. Today, the fisah are almost exclusively founds in Tonlé Sap lake and Tonle Sap river. It is unknown whether this constitutes one population, or whether there are two distinct ones. The fish is closely related to the Iridescent shark, which is also known as Pangasius.