The Vampire Tetra Hydrolycus scomberoides is a remarkable characin, but it is not your typical tetra. One look at the mouth of this fish and there will be no doubt that the Payara is a vicious carnivore. This incredible fish has two large fangs on its lower jaw. These fangs can be 4 to 6 inches long. In fact, the two main lower teeth are so long that upper jaw has holes for them to fit into.
The Payara are mainly known as a game fish and are prized by fisherman for their fighting ability. This is a member of the Cynodontidae family, which are called Sabre Toothed Tiger Fish, Dogtooth Characins, or Dogteeth Tetras. The Hydrolycus genus consists of four species. Collectively, they are called Pirandirá or Payara. Its common names are Vampire Tetra, Vampire Characin, Payara Characin, and Sabre Toothed Tiger Fish.
Payara are fast and aggressive feeders. These fish usually swallow their prey whole but will sometimes chop them into smaller, bite-sized pieces. They get large, too, so if you want to keep one as a pet, be prepared to have a very high feeder-fish bill. In fact, it can grow to about twice the size of its almost identical looking relative, the Sabertooth Characin Hydrolycus armatus. This fish can reach up to about 4 feet (117 cm) in length and weigh up to 40 lbs (18 kg), though aquarium specimens are usually only reach a quarter of that size, around 12 inches.
The Vampire Tetra can be kept in a large aquarium, but it takes a lot of work by a very advanced hobbyist to accomplish this. They are occasionally available and will readily adapt to aquarium life, but they are most often short-lived. They often only survive for 6 months to a year in captivity, with just a few having been reported as living up to 2 years. Their short lifespan is due, in part, to their diet and their need for a top quality environment. Vampire Characin need a varied diet, so just feeding them goldfish is inadequate. Sometimes, Payara refuse to feed. It seems that once they reach about 12 inches, they mysteriously die.
A school of Payara will need an extremely large aquarium. Young specimens will loosely school with their own kind, but adults are voracious predators and should be kept alone. Although they school loosely in the wild, they become less tolerant with a crowd. As they mature, they are not good community fish. In nature, the bulk of their natural food is the Piranha. Payara also need optimal water conditions in captivity. In the wild, these fish have different environments, depending on their age. Younger fish will avoid areas where there is strong water flow, but mature specimens will move into waters with faster currents. Providing Payara with these different environments as they age, as well as a wide variety of prey, takes the right type of dedicated hobbyist.