Red-bellied piranha in a tank

27 Fascinating Facts About Piranha

With many myths surrounding the Piranha fish, you may be wondering what the real truth about them is. It is an enigma of a fish, with many falsehoods circulating as myths around the internet.

In short, they are mostly omnivorous fish that exist in the Amazon basin primarily, with a preferred diet of fish, insects, fruit and plants. They will attack larger animals if the animal has already passed away. Natives to the area, from Peru to Brazil all swim in the Amazon without fear of attack. Most bites on humans are on the extremities, such as toes, feet and fingers. While not being a cuddly fish, they are far from the ravenous frenzied monsters of the films.

In fact, they are a most fascinating fish that has been on the planet many times longer than we have.

Fact 1 – They Require Warm Water to Survive

Piranha lives exclusively in the Amazon basin and surrounding lakes. The Amazon according to the United States Geological Service (USGS) is between 70 and 88 degrees Fahrenheit along its 6400 km length. They also will not eat food below 54 degrees Fahrenheit.

Amazon river
The Amazon river: 70 – 88 degrees Fahrenheit

Fact 2 – Piranha Have Different Colors

Piranhas come in different colors; some are silvery with orange undersides, some have red colors while others are completely black. The common Piranha species have deep bodies, with saw-edged bellies. They are large with generally blunt heads with strong jaws and scissor-shaped teeth.

1 black piranha
A Sole Black Piranha

Fact 3 – The Number of Piranha Species is Not Certain

Scientists separate ‘true piranhas’ from the herbivorous members of the of the genus. There is only four true piranha genus which includes genus Pygocentrus, genus Piraya, and Natteri. The exact number of Piranha species is not known and is estimated to be more than 30 but less than 60 species. Newer species of Piranha are being discovered continuously.

Fact 4 – The Piranha is a Medium Sized Fish

Although Piranhas are feared to be ferocious predators, they are small to medium sized fish which generally grow to around 30cm. There are some that grow to 80 cm, and their average weight is about 10 lbs across the different species of the fish. The extinct mega-piranha species was estimated to be about 100cm.

caught piranha
A Fisherman With a Caught Piranha

Fact 5 – They Breed in April and May

Piranhas breed seasonally during the rainy season, which is typically around April and May in the Amazon region. During mating, a pair of Piranha prepare a nest in the mud, where the female can lay her eggs which the male letter fertilizers. The female Piranha lays almost 5,000 eggs which are fertilized and well protected in their early days. The survival rate for the young ones is estimated to be about 90 percent as the older fish protect them until they can survive on their own.

Fact 6 – They Mate in Pairs

During the mating season, the female’s abdomen swells as it produces eggs which are ready to be laid. The male, on the other hand, deepens its colors as they prepare for mating. During this season the Piranhas are more aggressive as they protect their little ones from external threats.

School of Piranha

Fact 7 – The Can Live up to 25 Years

When the piranhas hatched from the fertilized eggs especially after only two days in warm water, they are protected by the adult fish during the early days of their lives. These young fish are known as fry as they grow they hide under seaweeds when under attack. The fry lives for five years before they become adult piranha fish.

Fact 8 – Their Bad Reputation is Mainly ‘Hollywoodized’.

Piranhas have the bad reputation of being dangerous carnivorous animals that can bite and kill a human, and strip flesh from the bones in minutes. This reputation stems from the claims of Presidents Roosevelt who visited Brazil and witnessed a school of starved piranha fish eats a cow in a feeding frenzy within minutes. The Hollywood has done injustice to the fish’s reputation as the films continue the narrative of a dangerous human-eating fish. The 1978 film ‘Piranha’ showed a military operation gone wrong where Piranhas escaped and feasted on unsuspecting swimmers. James Bond villains have done it no favors either.

Man in Piranha Pool

Fact 9 – Most Piranhas are Omnivores

Piranhas are thought to be carnivorous, but the fish is omnivorous, they will eat anything from seeds, plant parts, and seaweeds. They are not hunters naturally as they eat meat from dead animals and other fish or weak and sickly animals. They are sometimes referred to as the vultures of the sea, as they only attack when they are hungry, during times when the food is scarce.

Fact 10 – Piranha Teeth are Used by Humans

Piranhas have sharp teeth that are arranged on both rows. The word Piranha literary translates to ‘toothfish’ in local Brazilian language ‘Tupi’. The adult fish is known to have interlocking teeth that line the jaws. A true Piranha’s teeth are described to be tricuspid; the middles crown is raised to about 4 millimeters tall. Scientists argue that it is useful in assaulting their prey. The tooth is said to be chiseled shaped with enamel covering the teeth like those of the whales. Local tribes use the teeth as tools.

Piranha Jawbone
Piranha Jawbone

Fact 11 – Piranhas Replace Their Teeth

Although Piranha teeth are intense, they are replaceable. Sharks are known to replace individual teeth, but Piranha replaces their teeth throughout their life. However, you will still find Piranha fish with missing lower teeth.

piranha jaw and teeth

Fact 12 – Piranhas Have a Very Strong Bite

Piranha fish possess such as strong bite, and will bite with quite a force. The Black Piranhas are the largest of the Piranhas and bites with force three times the weight of its body estimated at a maximum force of 72 pounds. Their jaws have powerful muscles which make about two percent of their bodies; thus the strong bite, they can even tear through bulletproof vests and steel rods.

Fact 13 – They’re Exclusive to South America

Most Piranhas located out of South America have probably been released into these habitats by poachers. Piranhas do not occur naturally in these regions since they are native to South America. Piranhas have found their way in almost all parts of the world as pets in aquariums and zoos.

Pictorial Amazon Basin

Fact 14 – Aquarium Piranha are Prohibited in Some States

Owning Piranhas is prohibited in some States so ensure that your State allows you to keep piranhas in home aquariums. The legislation is stop people dumping the fish they do not want any more into the wild rivers causing disturbance to the ecosystem. Piranhas feed on other fish, and seaweeds without discrimination as they are referred to as the vultures of the sea, they might, therefore, interfere with the natural ecosystem of a river system.

Fact 15 – Piranhas Can Become Cannibals

Although a typical Piranha diet consists of fruits, seeds, crustaceans, fish and seaweed, some Piranhas are cannibals. An average fish consumes almost an eighth of its body mass which consists mostly of scavenged scraps. Piranhas are known to eat other fish species as they happily bite their fins as they pass by, however during dry spells when there is scarce food they can eat living or dead Piranha.

Fact 16 – Humans are Not Part of the Piranha Diet Unless Dead

Humans will most likely only be attacked by Piranhas when they are dead or dying. The idea of a school of Piranha fish feeding on living humans is a legend promoted by notable Hollywood movies. Cases of attacks in South America indicate that the bodies washed offshore was deceased before the Piranhas ate them. It is, however, dangerous to swim in water infested by these fish as they can bite off flesh from your body especially if food is scarce.

Dead body from Piranha

Fact 17 – Piranha Immobilize Their Prey Before They Attack

When attacking Piranhas immobilize their prey by biting the tail and the eyes, in a lab setting an experiment indicated that Piranhas would bite these parts first. This is a tactic for survival for the fish since they are small in size and would not overcome the enemy otherwise.

Fact 18 – The Piranha Barks

Piranhas bark under different circumstance as a means of communicating especially with their own, and other fish species. When they feel threatened by another fish, they will make noise that the scientists have named ‘quick calls’ to scare the enemy away. They make these noises by grinding their teeth or contacting and relaxing the muscles of the swim-bladder that is filled with air.

the piranha bark

Fact 19 – Piranha School to Give a Sense of Security for the Fish

It was believed that Piranhas stayed in schools for strength, but observational results from fish experts indicate that these fish run in packs for safety. Piranhas are not apex predators, they are mostly gatherers they only prey on small fish, crustaceans, and worms. They are however prey to river dolphins, caimans, birds and other large fish. Traveling in packs is for safety as the inner fish do not get an attacked, and this is one of the survival techniques for the fish.

piranha school
A Piranha School

Fact 20 – Piranha Will Only Attack Humans When They Feel Threatened

The only time the Piranhas might attack humans is if they feel their eggs are about to be disturbed. Like any other wild animal, the Piranha will leave you alone if you do not disturb their peace. They will however likely to bite you if they is scarce food in their natural habitat. They might bite off some small chunk of flesh if you go threatening them. Leaving them alone, they will not naturally approach you.

Fact 21 – They Are Attracted to Noise, Splashing, and Blood

The fish is attracted to splashing, noise, and blood and can smell blood from miles away, thus if you are bleeding stay away from Piranha infested water as they might think that you are a good meal. Noise and splashing in Piranhas are associated with fruits falling into the water as they might think that it is time for a meal. Generally, these things break the symmetry of the water and are the death knell for the creature doing it.

A study was done in 1972 to prove this very point.

A Piranha Attack

Fact 22 – Piranhas Make Great Soup

Piranhas make great grilled meat and soup, although in some parts of the Amazon it is a taboo to eat any predatory fish including the Piranhas. In some parts of Brazil, however, the fished is grilled and garnished with lime and served to tourists and locals on a banana leaf. Humans eat more Piranha than the other way around, so we can abandon the myth and enjoy the delicious Piranha soup, which according to nutritionists contains essential Omega-3 and Omega-6 fatty acids.

Fact 23 – Piranhas Need an Aquarium that Resembles Their Natural Habitat

If you decide to keep piranha fish in an aquarium ensure that the aquarium is spacious as the fish love their space. They do not survive well in confined aquariums. Make sure that the fish is well fed to avoid cannibalism and attacking the  other fish in the aquarium. Ensure that you provide plants in the aquarium where the fish can hide, and spawning shawls in the breeding aquarium to keep the eggs in one place just like the mud in their natural environment.

Piranha Aquarium
A Piranha Aquarium

Fact 24 – They Are a Non Migratory Species

They are not a migratory species, preferring to remain in the same area all of their lives. They only travel to seek out conditions conducive to breeding and spawning during periods of increased rainfall.

Fact 25 – When Attacking Fish They Go For The Eyes and Fins First

In what is clearly an early strike designed to disable and disorientate the prey the first fish in an attack will go for the eyes or the fins. Deprived of sight and the ability to manoeuvre the fish becomes unable to either resist or flee the attack. Further, it prevents fighting back and is essential for survival.

Fact 26 – They’ve Been in the Amazon Region for 9 Million Years

Although it seems an impossibly long time, a study in 2007 found that their common ancestry goes that far back. Modern Piranha are only thought to have been around for 1.8 million years.

Photo of school of Piranha

Fact 27 – They Can Smell Blood

With a sense that makes much more sense in a Hollywood movie, a Piranha, being a scavenger with a nickname of ‘vultures of the water’ can tell when there is blood in the water. They can sense a drop of blood in around 200 litres of water, which is around 3.5 bathtubs. This is sense they also share with sharks.


So there you have it. Hopefully you are a little more knowledgeable about Piranha than you were before.

While not being cuddly pets, they are far from the monsters that most people would have you belive. In fact, humans hunt the Piranha so they have more to fear from us than we do from them.

We are only likely to be attacked it the food is scarce, they feel they are defending themselves or you are about to disturb or attack the eggs during spawning season.

Just don’t tell the producers of the next James Bond film.


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