Red-bellied piranha (Pygocentrus nattereri)

Often feared because of its seemingly aggressive and frenzied attacks ⁽³⁾, the red-bellied piranha (Pygocentrus nattereri) has a reputation as a voracious predator, with razor-sharp teeth and an insatiable appetite ^{(2) (4)}. Although it is extremely variable in appearance ⁽³⁾, the red-bellied piranha takes its name from the characteristic red belly, which is often a deeper, more intense red in the male piranha, while the rest of the body is usually grey, with silver flecked scales, sometimes appearing creamy-brown on the sides ^{(2) (5)}. Blackish spots are often apparent behind the gills, and the anal fin is usually black at the base, while the pectoral and pelvic fins vary from red to orange ⁽²⁾. The red-bellied piranha also has a dark grey head that is orange-red below, and silvery, red-flecked eyes ⁽³⁾.

Size

Length: 28 - 33 cm ⁽²⁾

Weight

up to 3.5 kg ⁽²⁾

Despite frequently being portrayed as a dangerous and unpredictable predator, the red-bellied piranha feeds mainly on fish, insects and aquatic invertebrates, such as molluscs and crustaceans. It may also feed on any small, terrestrial animals it encounters, as well as fruits, seeds, algae and aquatic plants ^{(2) (4) (5) (6)}. The sharp, triangular teeth of the red-bellied piranha interlock when the mouth is closed, making it extremely efficient at biting through food items ^{(3) (8)} and its powerful jaw arrangement and flat, blunt snout give the fish the ability to attack and bite with remarkable force.

The red-bellied piranha lives in shoals, although it does not exhibit group hunting behaviour ⁽⁷⁾. Occasionally the red-bellied piranha will enter into a ‘feeding frenzy’, where schools of piranha converge on a large item of prey and strip it clean within minutes. This particular behaviour contributes to the formidable reputation of the red-bellied piranha, but the frenzies are not usually random attacks, and are more often the result of provocation or starvation ^{(4) (5)}.

Breeding occurs during the rainy season, usually peaking over a two month period that can vary depending on location ^{(4) (5) (6)}. The female lays around 5,000 eggs on newly submerged vegetation ⁽⁶⁾, often in bowl-shaped nests that have been built by the male ^{(2) (4)}.

Widely distributed throughout the South American continent, the red-bellied piranha is found in tropical freshwater rivers in Argentina, Bolivia, Brazil, Colombia, Ecuador, Guyana, Paraguay, Peru, Uruguay and Venezuela ^{(2) (4) (5)}.

Typically found in white water rivers ^{(2) (4) (6)}, and in some streams and lakes ⁽⁵⁾. In certain areas, the red-bellied piranha may also inhabit flooded forests (such as those found throughout the Brazilian Amazon) ⁽⁷⁾.

The red-bellied piranha has yet to be classified by the IUCN.

This species is not currently considered threatened. However, because of its popularity as an aquarium species in some parts of the world, collection and trade may pose a low risk to the red-bellied piranha ⁽⁵⁾.

There are currently no specific conservation actions targeted at the red-bellied piranha.

View information on this species at the UNEP World Conservation Monitoring Centre.

Find out more about conservation of the red-bellied piranha’s habitat:

• The Nature Conservancy:
  http://www.nature.org/initiatives/freshwater/

Find out more about other conservation projects throughout South America:

• Wildlife Conservation Society:
  http://www.wcs.org/saving-wild-places/latin-america-and-the-caribbean.aspx

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

Algae

Simple plants that lack roots, stems and leaves but contain the green pigment chlorophyll. Most occur in marine and freshwater habitats.

Anal fin

In fish, an unpaired fin on the under surface of a fish, behind the anus.

Crustaceans

Diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, slaters, woodlice and barnacles.

Invertebrates

Animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones), echinoderms, and others.

Molluscs

A diverse group of invertebrates, mainly marine, that have one or all of the following; a horny, toothed ribbon in the mouth (the radula), a shell covering the upper surface of the body, and a mantle or mantle cavity with a type of gill. Includes snails, slugs, shellfish, octopuses and squid.

Pectoral fins

In fish, the pair of fins that are found one on each side of the body just behind the gills. They are generally used for balancing and braking.

Pelvic fins

In fish, the pair of fins found on the underside of the body.

White water rivers

Streams or rivers that deposit a heavy load of sediment (clay, silt and gravel). The typical form of large rivers in lowland tropical rainforests, they drain more fertile soils and are usually opaque and pale brown in colour.

1. UNEP-WCMC (August, 2010)
   http://www.unep-wcmc.org/
2. World Association of Zoos and Aquariums (August, 2010)
   http://www.waza.org/en/zoo/choose-a-species/fishes/bony-fishes/pygocentrus-nattereri
3. Burnie, D. (2001) Animal. Dorling-Kindersley, London.
4. The Nature Conservancy (August, 2010)
   http://www.nature.org
5. Bristol Zoo Gardens (August, 2010)
   http://www.conservationpark.org.uk/red-bellied-piranha
6. Duponchelle, F., Lino, F., Hubert, N., Panfili, J., Renno, J-F., Baras, E., Torrico, J.P., Dugue, R. and Nuñez, J. (2007) Environment-related life-history trait variations of the red-bellied piranha Pygocentrus nattereri in two river basins of the Bolivian Amazon. Journal of Fish Biology, 71: 1113-1134.
7. Queiroz, H. and Magurran, A.E. (2005) Safety in numbers? Shoaling behaviour of the Amazonian red-bellied piranha. Biology Letters, 1: 155-157.
8. Campbell, A. and Dawes, J. (2004) Encyclopedia of Underwater Life. Oxford University Press, Oxford.