Red-Bellied Piranha Fact File
The World's Most Feared Fish!
Red-bellied piranhas have taken on a feared reputation in pop culture initially from reports of a trip to the Amazon by Teddy Roosevelt and later furthered by the 1970s film, Piranha.
These fish are fitted with a strong jaw and sharp teeth designed to tear fish which are used to eat insects, bird chicks and fish. When feeding on fish they primarily nip parts of their body such as fins.
When hunting they move in shoals for protection. Larger shoals have also been seen to work together to attack large prey such as the capybara.
This species has not been evaluated by the IUCN but has a wide range across South America. In some areas they are hunted for food.
Read on to learn more about these feared fish.
What does the Red-Bellied Piranha look like?
Their coloration is variable across their range but one characteristic is consistent across their range which is the red belly scales from which their name is taken. Their chin and caudal fins also take on this red color. Depending on the population their sides may be pale brown, olive or bluish-grey. This is patterned with gold flecks.
A large set of fleshy lips are present on the face which hide most of the large teeth.
An average red-bellied piranha will measure 15-20cm (6-8in) long though some extraordinary large individuals have been recorded at lengths of up to 50cm (20in). They weigh up to 1.8kg (4lbs).
How does the Red-Bellied Piranha survive in its habitat?
Piranhas are best known for the ferocious appetite and to assist with this their strong, triangular shaped jaw contains a number of triangular teeth.
They are able to locate food through their keen sense of smell. Prey can be found using the lateral line sensors which are located along their body. These pick up changes in nearby water pressure.
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What does the Red-Bellied Piranha eat?
Red-bellied piranhas are carnivores. These fish hunt for insects, snails and worms. While they are not often able to consume full fish they will nip parts of their fins off using their sharp teeth. Large groups have shown the ability to take down species as large as the capybara.
Small amounts of algae and aquatic plants may also be consumed by this species.
When hunting these fish will lie in ambush among nearby vegetation before shooting out to attack passing prey. They have also been seen to wait in areas where birds are nesting for a chick to fall in to the water.
If blood enters the water these fish tend to become more aggressive.
Learn more about the Red-Bellied Piranha in this video from Nat Geo Kids on YouTube
Where do you find the Red-Bellied Piranha?
South America is the native home of the red-bellied piranha. Here they can be found in Argentina, Brazil, Bolivia, Colombia, Ecuador, Guyana, Paraguay, Peru and Venezuela through the Amazon basin.
Due to human introductions this species has been seen outside their range in areas such as China, the United Kingdom and the United States. Most of these come from releases of pets.
Where can the Red-Bellied Piranha survive?
This species is found in freshwater river systems through the Amazon basin.
Credit: Public Domain
How does the Red-Bellied Piranha produce its young?
Egg laying takes place during the wet season and success is heavily tied to the level of flooding which occurs.
Their courtship display involves the pair swimming around one another in circles.
Females deposit their eggs in to a bowl which is formed in sediment by the males who then fertilize them externally. This nest is sited near plants to which the eggs will stick.
Males remain near eggs they fertilize them and fan them with their fins. This is continued for the nine to ten day incubation period.
What does the Red-Bellied Piranha do during its day?
These fish will form groups of between 20 and 30 birds. They will hunt together. Research has shown that when in larger shoals they can breathe easier and are less vulnerable to attack. As a result larger shoals are most commonly seen in shallow water where there are more threats.
Small piranha are active during the day. As they grow they tend to take on a more crepuscular activity cycle being active at dawn and dusk.
The red-bellied piranha produces a vocalization which has been likened to a bark. They can also make one that sounds like a beating drum. These are produced through vibrations in the swim bladder.
Credit: Public Domain
Predators and Threats
What stops the Red-Bellied Piranha from surviving and thriving?
Natural predators of the red-bellied piranha include crocodiles, birds and large fish such as catfish.
In areas of their range this species is considered a popular food.
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This species may also be known simply as the red piranha.
Modern piranhas are said to have diverged from their most recent ancestor roughly 9 million years ago.
The word 'piranha' is take from the Tupí language spoken in Brazil. It translates as 'tooth fish.'
Credit: Public Domain
H, T., 2022. 5 Things I Learned about the Red-Bellied Piranha (Pygocentrus nattereri) – Greater Cleveland Aquarium. [online] Greaterclevelandaquarium.com. Available at: <https://www.greaterclevelandaquarium.com/5-things-red-bellied-piranha/> [Accessed 8 April 2022].
Georgia Aquarium. 2022. Red Piranha – Georgia Aquarium. [online] Available at: <https://www.georgiaaquarium.org/animal/red-piranha/> [Accessed 8 April 2022].
Smithsonian's National Zoo. 2022. Red-bellied piranha. [online] Available at: <https://nationalzoo.si.edu/animals/red-bellied-piranha> [Accessed 8 April 2022].
The Dallas World Aquarium | #DWAZOO. 2022. Red-bellied piranha | The Dallas World Aquarium. [online] Available at: <https://dwazoo.com/animal/red-bellied-piranha/> [Accessed 8 April 2022].
Owlcation. 2022. The Red-Bellied Piranha: An Analysis. [online] Available at: <https://owlcation.com/stem/The-Red-Bellied-Piranha-An-Analysis> [Accessed 8 April 2022].
Thompson, H., 2014. 14 Fun Facts About Piranhas. [online] Smithsonian Magazine. Available at: <https://www.smithsonianmag.com/science-nature/14-fun-facts-about-piranhas-180951948/> [Accessed 8 April 2022].