Red-Bellied Piranha (Serrasalmus nattereri)


Class: Actinopterygii
Order: Cypriniformes
Family:    Characidae
Size:    Length: 8 to 15 inches (20 to 38 cm)
Weight: Up to 3 lbs (1.4 kg)
Diet: Fish, birds, reptiles, rodents, small mammals and sometimes carrion
Distribution: South America
Young:  Several thousand eggs at a time
Animal Predators:  Unknown
IUCN Status: No special status
Terms: Young: Fry  Group: Shoal
Lifespan: Unknown



·         The largest piranhas grow to be about two feet (60 cm) long.

·         Three or more species of piranhas are usually found in the same area.

·         The name piranha comes from the South American native language Tupi-guarani and means cuts the skin.

·         It is illegal to keep piranhas in 21 states of the United States.



Red-bellied piranhas are relatively small piranhas. They are blue-grey to brownish on their upper body. In fry and juvenile specimens, the throat, abdomen and pectoral, ventral and anal fins are bright red but this colouration fades with increasing age. They have short, powerful jaws with 28 to 31 triangular, inter-locking, razor sharp teeth. The word used to describe scissors is “piranha” for native people living along parts of the Amazon River, because long ago, Indians in the region first used piranha jaws as a cutting tool. All piranha species have a single row of sharp, triangle-shaped teeth in each jaw. 



Red-bellied piranhas live in the warm fresh water of the Amazon and Orinoco river basins in South America.


Feeding Habits

Their teeth resemble very sharp pinking shears, but they do not use them to chew—piranhas swallow their food whole. Their teeth are used only to break off chunks of food. Red-bellied piranhas eat fish, birds, reptiles, rodents and other small mammals that venture into the water. They also feed on carrion, and it is believed that when human skeletons have been found in rivers where piranhas live, that they are the bodies of men who drowned, and their dead flesh was then eaten by the piranhas. Piranhas feed in groups called shoals. As piranhas feed, they dart up to the surface and then swim back down deep. Often after one piranha makes this move, a feeding frenzy will ensue. 



Female piranhas lay several thousand eggs near water plants during the rainy season, on the floor of the river. The eggs stick to the plants and the male swims by to fertilize them. Although knowledge of mating and reproduction of piranhas in the wild is limited, it is believed that the pair stays close to their eggs to guard them. In two to three days, the eggs hatch and the young piranhas stay on the bottom where they can hide among the plants until they are large enough to defend themselves against predators. Juvenile piranhas eat mainly insects and crustaceans. They become old enough to breed when they are approximately one year of age.



Piranhas are famous for being man-eaters, but actually, there is no recorded instance of a person being killed by piranhas. Of the 18 piranha species, only four are considered dangerous. The red-bellied piranha is one of those, because it will bite when it is underfed, overcrowded or threatened. They also bite anything that moves where blood is present in the water. Fishermen have lost fingers by pulling a piranha out of the water in a net and then allowing it to throw itself around on the bottom of the boat. Some species of piranhas actually have a mostly vegetarian diet, eating seeds and fruit that fall into the water. Piranhas are sold as pets, but they are extremely shy aquarium fish and only come out at feeding time. Most piranhas cannot be kept with other fish, because they consider them food. In the wild, they live in large packs and because of their enormous appetites, spend most of their time searching for food.



Piranhas are not a conservation concern. 



Piranha Wildlife Fact File, IM Pub, US