Piranhas

Relationship with humans
Piranha teeth are often used to make tools and weapons by the indigenous population. Piranhas are also popular as food, although if an individual piranha is caught on a hook or line, it may be attacked by other (free) piranhas.
Piranhas are commonly consumed by subsistence fishermen, and often sold for food in local markets. In recent decades, dried specimens have been marketed as tourist souvenirs. Piranhas occasionally bite and sometimes injure bathers and swimmers. A piranha bite is considered more an act of carelessness than that of misfortune, but piranhas are a considerable nuisance to commercial and sport fishers because they steal bait, mutilate catch, damage nets and other gear, and may bite when handled.
Several piranha species appear in the aquarium trade. Piranhas can be bought as pets in some areas, but they are illegal in many parts of the United States.