The payara is often called the vampire fish because of its two long canine-like teeth.
Payara usually refers to Hydrolycus scomberoides, a predatory characin native to rivers of tropical South America, particularly the Amazon and Orinoco basins. Its lower jaw has two prominent fang-like teeth that fit into protective sheaths in the upper jaw when the mouth closes.
The fish is streamlined and muscular, allowing it to chase smaller fish in fast-flowing water. It is valued as a game fish and is also occasionally kept by specialist aquarists, although its size, aggression, and dietary needs make it unsuitable for most home aquariums.
The name vampire fish can be misleading. Payara are not mammals, bats, or true eels, and they are not piranhas. They belong to the characin order, which also includes tetras and piranhas, but their elongated body and oversized teeth give them a very different appearance. Several related Hydrolycus species also have fang-like teeth, so the common name is sometimes used broadly.