Interesting facts about piranhas


A piranha is a ferocious freshwater fish.

Piranhas live in lakes and rivers in South America.

They require warm water to survive and do not eat when the water temperature is less than 12°C (54°F) degrees Fahrenheit.

The total number of piranha species is unknown and contested, and new species continue to be described. Estimates range from fewer than 30 to more than 60.

They live up to 25 years in the wild and 10-20 years in captivity.


Piranhas are normally about 15 to 25 centimeters (6 to 10 inches) long, although some specimens have been reported to be up to 50 centimeters (20 inches) in length.

Piranhas range in color from yellow to steel-grey to bluish to partly red to almost black.

A piranha’s mouth is lined with a single row of razor-sharp, triangular teeth. They have a distinct under-bite, which means the bottom row of teeth is constantly exposed.

piranha teeth

It’s not uncommon for piranhas to lose teeth throughout their lifetime. But, while sharks replace their teeth individually, piranhas replace teeth in quarters multiple times throughout their lifespan.

Most piranhas are shy and non-aggressive, unless they are hunting or protecting their young.

Black piranhas and red-bellied piranhas are considered the most dangerous and aggressive toward humans.

Despite the carnivorous nature of the piranha, the piranha is actually an omnivore and will eat almost anything that it can find.

piranhas feeding

A typical piranha diet consists of insects, fish, crustaceans, worms, carrion, seeds, fruit and other plant material.

They will also eat whatever meat crosses their path, and because they hunt in groups, they can take down large animals.

Piranhas rarely attack humans. Fatal attacks are extremely rare.

These voraciously hungry fish tend to have a lurk-and-ambush style of attack that occurs en masse, with large groups of piranha feeding at once.

Shoals of piranhas can be found in numbers of up to 1000.


Various stories exist about piranhas, such as how they can dilacerate a human body or cattle in seconds. These legends refer specifically to the red-bellied piranha.

Experiments have shown that piranhas have an amazingly acute sense of smell, which aids them in locatin food in the often murky waters of their native habitat.

Piranhas have the standard respiratory system that most fish have. They take water in through their gills and then absorb oxygen from the water. The oxygen then goes to the blood stream. After the oxygen is absorbed the carbon dioxide is exhaled through the gills.


The female lays around 5000 eggs then the male will fertilize the eggs. The male will then protect the eggs and become very territorial of them. The piranhas will spawn from the eggs after a few days. They have two spawning periods, one in April/May and a second in the late summer time.

Many animals prey upon piranhas (especially young piranhas), including other piranhas, larger fish, caimans, water snakes, turtles, birds, otters and people.

The word piranha literally translates as “tooth fish” in the indigenous Brazilian language of Tupi.


Native people of South America use piranha teeth for tools and weapons.

When American President Theodore Roosevelt visited Brazil in 1913, he went on a hunting expedition through the Amazon Rainforest. While standing on the bank of the Amazon River, he witnessed a spectacle created by local fishermen. After blocking off part of the river and starving the piranhas for several days, they pushed a cow into the water, where it was quickly torn apart and skeletonized by a school of hungry piranhas.

Piranhas can be bought as pets in some areas, but they are illegal in many parts of the United States. It is illegal to import piranhas into the Philippines and violators could face six months to four years in jail.

The most common aquarium piranha is Pygocentrus nattereri, the red-bellied piranha.

Films have often portrayed piranhas as aggressive, insatiable predators.

Piranha (1978) and Piranha II: The Spawning (1981) perpetuated the piranha’s sinister image by showing murderous piranha fish biting and eating humans. In the 2010 film Piranha 3D, a previously unknown piranha is discovered.

Fossil evidence puts piranha ancestors in the continent’s rivers 25 million years ago, but modern piranha genera may have only been around for 1.8 million years.

Piranhas have also been discovered in the Kaptai Lake in southeast Bangladesh and in the Lijiang River in China. Research is being carried out to establish how piranhas have moved to such distant corners of the world from their original habitat.