Red Tail Payara Vampire Tetra (Hydrolycus tatauaia)

The Vampire Tetra 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. 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. 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.