The arapaima, pirarucu, or paiche (Arapaima) is a genus of bonytongue native to the Amazon River in Brazil. They are the largest freshwater fish of South America. Arapaima can reach lengths of more than 2 m (6 ft 7 in), in some exceptional cases even more than 2.5 m (8 ft 2 in) and over 100 kg (220 lb). The maximum recorded weight for the species is 200 kg (440 lb).
The Mekong giant catfish is a species of catfish (order Siluriformes) in the shark catfish family (family Pangasiidae), native to the Mekongbasin in Southeast Asia. In Thai folklore, this fish is regarded with reverence, and special rituals are followed and offerings are made before fishing it.
The giant barb or Siamese giant carp is the largest species of cyprinid in the world. These migratory fish are found only in the Mae Klong, Mekong and Chao Phraya river basins in Indochina. It has declined drastically due to habitat loss and overfishing, and it is now considered Critically Endangered.