The term "paku" refers to a type of fish commonly found in freshwater environments, particularly in the rivers and lakes of South America. It belongs to the family Serrasalmidae and is known for its distinctive flat body and large, sharp teeth. Paku are often confused with their relatives, the piranha, but they primarily feed on fruits, nuts, and seeds rather than meat. Paku are popular in aquaculture and are sometimes kept in home aquariums due to their unique appearance and behavior. They can grow quite large, reaching lengths of up to 3 feet, and require ample space and a suitable environment to thrive.