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.
- Biogeographic Regions
- neotropical
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)
- Habitat Regions
- tropical
- freshwater
- 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.
- Other Physical Features
- ectothermic
- heterothermic
- bilateral symmetry
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.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- oviparous
Behavior
- Key Behaviors
- natatorial
- motile
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.
- Primary Diet
- omnivore
- 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 .
Economic Importance for Humans: Positive
Pygocentrus nattereri
is one of the most commonly used piranhas in the aquarium trade.
- Positive Impacts
- pet trade
Economic Importance for Humans: Negative
Pygocentrus nattereri
is considered one of the more dangerous and aggressive species of piranha.
- 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.
Additional Links
Contributors
William Fink (editor), University of Michigan-Ann Arbor.
Brian Putz (author), University of Michigan-Ann Arbor.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- freshwater
-
mainly lives in water that is not salty.
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- 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.
- 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.
- 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).
- 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
- fertilization
-
union of egg and spermatozoan
- external fertilization
-
fertilization takes place outside the female's body
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- carrion
-
flesh of dead animals.
- pet trade
-
the business of buying and selling animals for people to keep in their homes as pets.
- omnivore
-
an animal that mainly eats all kinds of things, including plants and animals
- natatorial
-
specialized for swimming
- motile
-
having the capacity to move from one place to another.
- tactile
-
uses touch to communicate
- chemical
-
uses smells or other chemicals to communicate
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.