Pygocentrus nattereriRedbelly piranha

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Geographic Range

Pygocentrus nattereri is found in South America. Pygocentrus nattereri can be found east of the Andes in the Parana-Paraguay and Amazon basin. They can also be found in rivers of northeast Brazil and the Guianas. (Fink, 1993; Uetanabaro, et al., 1993)

Habitat

Pygocentrus nattereri is typically found in whitewater streams in South America (Saint-Paul 2000). However, the species is not found typically in blackwater streams (Fink 1993) (Fink, 1993; Saint-Paul, et al., March 2000)

  • Aquatic Biomes
  • rivers and streams

Physical Description

Pygocentrus nattereri physical characteristics vary with location, population, and age. In juvenile P. nattereri there are differences in physical characteristics depending on the size of the fish. A change in color pattern does seem to develop as size increases. The thickening body tissue tends to cause the black internal line of the anal fin to disappear and both the number of body spots and the density of melanophores increases with growth. Adult specimens also tend to vary in color pattern and body size with geographic location. Generally P. nattereri is reddish-orange ventrally and silver-gray dorsally. The fins vary in color as well, with a black dorsal fin, black anal fin, and reddish-orange pectoral fins. The lateral color of the fish is a gray to silver- gray. (Fink, 1993)

Reproduction

Pygocentrus nattereri seems to have a type of courtship display that involves swimming in circles. This results in ventral-to-ventral interactions among the male and female. Eggs are placed in the sediment, in bowl shaped nests. These nests are around 4-5 cm in depth and 15 cm in diameter. The eggs are in clusters and are attached to the bottom vegetation. There may also be a relationship between the times of the spawning and the time of the wet season. (Uetanabaro, et al., 1993)

  • Breeding season
    Spawning seems to occur during the wet season.

Behavior

Communication and Perception

Food Habits

Foraging methods vary in different life stages of P. nattereri. During the day, smaller fish (80-110 mm) search for food. At dawn, late afternoon, and early evening the larger fish (150-240 mm) search for food. Pygocentrus nattereri groups gather in vegetation in order to wait for prey. The group typically includes around 20-30 fishes. In the daytime P. nattereri can be seen lurking or ambushing prey. Two other methods for obtaining food employed by P. nattereri are chasing and scavenging. The hunting mode of chasing was seen after the fish lie and wait in vegetation. The fish then proceed to swim after and eat the fish. P. nattereri has a wide variety of food in its diet, including fins, scales, fish (pieces and whole), insects, snails, and plants. The plant intake of the animal may be an active way of gaining food supplies while scanning for prey. (Sazima and Machado, 1990)

  • Animal Foods
  • fish
  • carrion
  • insects
  • mollusks
  • Plant Foods
  • leaves
  • fruit

Ecosystem Roles

An interesting relationship between P. nattereri and Serrasalmus marginatus has developed. Serrasalmus marginatus has been seen taking crustacean parasites off the bodies of P. nattereri.

Mutualist Species

Economic Importance for Humans: Positive

Pygocentrus nattereri is one of the most commonly used piranhas in the aquarium trade. (Fuller, et al., 1999)

Economic Importance for Humans: Negative

Pygocentrus nattereri is considered one of the more dangerous and aggressive species of piranha. (Fuller, et al., 1999)

  • Negative Impacts
  • injures humans
    • bites or stings

Conservation Status

Pygocentrus nattereri has been introduced to the freshwaters of the United States on numerous occasions. Introductions have been reported in Florida, Hawaii, Massachusetts, Michigan, Minnesota, Ohio, Oklahoma, Pennsylvania, Texas, and Virginia. The fishes were probably releases from aquariums. When a piranha is found in a lake, many state agencies use the chemical rotenone to kill the fishes. (Fuller, et al., 1999)

Contributors

William Fink (editor), University of Michigan-Ann Arbor.

Brian Putz (author), University of Michigan-Ann Arbor.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carrion

flesh of dead animals.

chemical

uses smells or other chemicals to communicate

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

freshwater

mainly lives in water that is not salty.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pet trade

the business of buying and selling animals for people to keep in their homes as pets.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

References

Fink, W. 1993. Revision of the Piranha Genus Pygocentrus (Teleostei, Characiformes). Copeia, 3: 665-686.

Fuller, P., L. Nico, J. Williams. 1999. Nonindigenous Fishes Introduced into Inland Waters of the United States. Bethesda, Maryland: American Fisheries Society.

Saint-Paul, U., J. Zuanon, M. Correa, M. Garcia, N. Fabre. March 2000. Fish Communities in Central Amazonian White- and Blackwater floodplains. Environmental Biology of Fishes, 57: 235-250.

Sazima, I., F. Machado. 1990. Underwater Observations of Piranhas in Western Brazil. Environmental Biology of Fishes, 28: 17-31.

Uetanabaro, M., T. Wang, A. Abe. 1993. Breeding Behaviour of the Red-Bellied Piranha, Pygocentrus nattereri, in nature. Environmental Biology of Fishes, 38: 369-371.