No other river is home to so many species of very large fish. The biggest include three species of "Probarbus" barbs, which can grow up to and weigh , the giant freshwater stingray ("Himantura polylepis", syn. "H. chaophraya"), which can reach at least in length and in width, the giant pangasius ("Pangasius sanitwongsei"), giant barb ("Catlocarpio siamensis") and the endemic Mekong giant catfish ("Pangasianodon gigas"). The last three can grow up to about in length and weigh . All of these have declined drastically because of dams, flood control, and overfishing.