Solitary Black piranha

The Black Piranha [also known as The RedEye Piranha]

The Black Piranha is one of the more common Piranhas. Not as famous as the Red-Bellied Piranha, its twin aggressive cousin, but it is predominant around the Amazon basin. As such, it holds just as much mystique as its more talked about brethren.  

In short, the Black Piranhas, also known as Red-Eye Piranhas are a freshwater fish primarily found in the Amazon basin. They are extremely tolerant of the diverse conditions within the basin, existing in black water lagoons and fast paced whitewaters. The are actually omnivores, with a typical diet of insects, fruits, worms, crustaceans and fish. It exists up to around 42 cm and has natural predators, such as the river dolphin, storks, egrets and caimans. It is most common around the Orinoco river basins and the Guiana Shield rivers and is a non migratory species. Like all Piranha, they can only survive in warm water. It is considered one of the more aggressive Piranha, but attacks on humans are rare. They do perform a ‘Piranha Frenzy’ but are actually solitary fish, which is unusual as most Piranha travel in schools. They are the biggest of the Piranha species and have the most powerful bite as well. A fearsome fish.

Single Black Piranha swimming in tank

The Classification Of Black Piranha

For a long while the taxonomy of the Black Piranha was known as Serrasalmus niger (ie Piranha Black). As the specific coloration of the type varies a bit across the Amazon basin from the darker blacks of the Peruvian Piranhas to the greys colorations of the Brazilian Piranhas it was changed.

It changed to Serrasalmus rhombeus (ie Piranha Rhombic body shape) as they had this common physical trait. They are now more commonly referred to by a Country prefix.

The Venezuelan ‘Serrasalmus rhombeus’ have the brightest red eyes and a grey body color, whereas the Peruvian Serrasalmus rhombeus are more black in the body color and have paler red eyes.

Identifying a Black Piranha

The Black Piranha as you might expect, also being called the Red-Eye Piranha can be identified by a solid grey or black body with a red eye.

They are known for their striking shape and are sometimes, rather confusingly referred to as the Rhombus Piranha. They typically vary in color, ranging from the Peruvian jet black to a lighter grey with bright red eyes, making the fish stand out amongst the other another Piranha species.

Serrasalmus rhombeus also, again not unexpectedly, has a rather rhombic looking body shape.

They are one of the largest species of the Piranha measuring about 32 centimetres on average. Large ones can measure 42 cm and they normally weigh close to 3 kgs and can live up to 25 years or more. Black Piranha, when kept under aquariums, love staying alone since they see other fish as being threatening to their existence.

Moreover they are hunters which can feed on other fish if they feel hungry or when they feel threatened.

Single Black Piranha

Black Piranha Characteristics

The lifespan of the Black piranha, varies a little with some claiming they live around 10 years, however some people have claimed they have known them to live for around 25 years. A lot depends on whether they are captive or wild.

A good average lifespan for the species might be around 15 years. Longer if they are well cared for.

It’s actually the biggest species of Piranha as well. It can grow up to around 40 cm and that would be a good sized fish. They are said to be slower growing than other Piranha, gaining a few inches per year. Thus a big 40 cm fish would be at least 10 years old.

It’s said that if you get bitten by a Black Piranha that you may not feel the bite as the teeth are so sharp, coupled with the most powerful bite of all piranha they cut away the flesh like a scalpel.

Sometimes, people only notice they have been bitten when they see the blood.

It’s also known for being a solo fish. It does not travel in shoals, like the more common Red-Bellied Piranha.


At a very young age, the Black Piranha may be more spotty than a solid color. As they age into adulthood, the silvery body with spots gives way to a more solid and even gray or black. The darkness of the ‘black color’ will depend upon water conditions, typically denoted by country location. Peruvian Black Piranha are famed for being almost jet black.


Perhaps the most distinctive way of identifying a Black Piranha is the very red eyes. It will be more distinctive as the Piranha matures into adulthood.

People have noted that the eye color changes as the body color changes to the more solid body color, which is typically when they are juvenile fish, say around 5 inches in length.

Where Do Black Piranha Live?

Black Piranha live throughout the Amazon basin, and they are said to prefer black waters (black tea in coloration). They’re found in most rivers, but they common the Albina Reservoir in Brazil. Most of the Piranha fish species are however found in this part of the Amazon.

The Orinoco river basins are a known habitat as well.

As they are found from Peru to Brazilian coastal waters, and are fished for in blackwater lagoons and hard whitewater rapids, they are thought to be very tolerant of different types of water. From the chemical make up to the amount of sediment and water flow.

The Black Piranha is evenly distributed in the freshwaters of the Amazon basin and will be found in Brazil, Bolivia, Colombia, Ecuador, Guyana, Paraguay, Peru and Venezuela. They prefer living in regions that are dense in plant population as they are a shy fish.

Orinoco river
The Orinoco River in the Amazon Basin

Typical Diet of Black Piranha

Although the Black Piranha are known for their sharp teeth and powerful bite, they are omnivore scavengers who will feed on plants, fallen fruits and small river animals. Insects and worms also make up their diet. They will however occasionally feed on invertebrates and small fish. Like most piranha they will rarely attack animals that are bigger than them in size, unless very hungry or threatened.

The Black Piranha is known as the vulture fish as they scavenge on dead or weak animals that are about to die. In aquariums they should be fed food that contain animal meats such as the earthworms, brine shrimp and bloodworms.

Some will learn to accept flakes as soon as they adapt to the tank. You should provide meet whether frozen or live to these fish, you should note that they do not eat rotting meat thus ensure that your meat is always fresh. Be careful on fresh meat which can introduce diseases to your fish.


The Black Piranha reproduces by egg laying in a nest. The female Black Piranha will lay her eggs in a safe reed bed in shallow water that anchors the eggs. The male Black Piranha will later fertilize the eggs and is responsible for taking care of the fry till they are safe on their own.

The breeding period for this fish is guided by the water hydrology which include the currents, temperature and tides. The Redeye Piranha will however breed during the rainy season which is around April and May in the Amazon region.

No Shoals of Black Piranha

The Black Piranha is a solitary fish that will travel on their own, but on rare occasions, especially during feeding frenzies or when they are under attack they will group themselves in a shoal.

This is atypical piranha behaviour.

Solitary Black piranha

Black Piranha Behaviour

In enclosed spaces, except for the purposes of feeding it is believed that the Black Piranhas are not as tolerant of their own species as other types of Piranha. It really is a solitary fish.

When placed together there is a good likelihood that they will attack their own. This seems to be cannibalistic behaviour.

As they are a solitary fish by preference, this is easy to achieve in nature. There is more than enough Amazon basin to go around. In an aquarium though this becomes problematic.

This behaviour distinguishes the Black Piranha from its brethren as they will live in schools of fish for protection. Large tanks are necessary if you wish to keep more than one Black Piranha in a tank. It is still recommended though that only one per tank is maintained to avoid injuries or death of one of them,

Is it the Most Aggressive Piranha

The Black Piranha is said to be one of the most aggressive piranha fish, no doubt with its myth boosting powerful bite. It has a very strong jaw and its body is very muscular.

It could be described as sinister looking, but in reality it is considered a rather shy fish.

Despite the size and razor sharp teeth, it is mostly omnivorous, and will bite other animals when really starving or threatened. It would be true to say, it is not aggressive if treated correctly and well fed.

It hunts on its own, not in packs like the more common Piranha, and therefore is even more wary of large animals in its presence. A shoal gives a sense of security.

It has the same kind of aggression that most of the Piranha do. Absent any threatening conditions it will leave you alone.

So compared to other Piranha it is considered aggressive, but they are somewhat misunderstood. The Red-Bellied Piranha is still considered the most aggressive of the species.

Wading in shallow water around reeds during the mating season in the Amazon has its risks though.

The Most Powerful Bite in History

The particular fish has a bite which is thirty times compared to its body weight. Big alligators do not produce this kind of bite as compared to their body sizes.

Ichthyologists (fish scientists) have said that the Black Piranha bite has the largest bite in history of the vertebrates.

It amounts to 30 times its own body weight.

That means a 7 lb Black Piranha bites with a 210 lbs per square inch bite force.

Couple this with razor sharp teeth and it is a fearsome biting weapon. As indicated earlier, this is why people are bitten by Black piranha often don’t notice the bite.

It is scalpel like in its precision and coupled with power, chunks of flesh are taken away almost painlessly.

Black Piranha Were Thought Responsible for the Brazilian Beach Incident

At the end of 2011, on the Paraguay river in Brazil ar a popular river beach resort (Daveron beach), hundreds of swimmers and bathers were

Obviously, the media coverage was not sympathetic to the Piranha

This says a lot about how the Piranha actually behave. Despite over 15 people being injured, resulting in bleeding, no-one died and everybody walked out of the river.

No feeding frenzies, and no schooled attacks. Individual people being individually bitten.

The preconditions were that it was one of the hottest days of the year, at the end of the dry reason after the first rains. This is when the Black Piranha is most likely to breed.

The resort is on the edge of a very shallow river edge flush with vegetation.

What most likely happened is, as the attacks happened when most people were in the water, and all of them were wading in shallow water and splashing around, is that the Black Piranha felt threatened.

They were most likely spawning Piranha who were defending their eggs, as every living animal does. It’s an instinct.

In almost certainly wasn’t the bloodthirsty attack that was portrayed, but the Piranha defending their nests.

The Black Piranha were defending themselves.

Black Piranhas for Aquariums

Black Piranhas have been kept in aquariums in most parts of the world. Beginners should be aware of their shyness. They can pretend to die or go on a ‘food strike’ when they are introduced to a new body of water.

They should be left alone as they are loners in the wild. keep them in a dark room away from explosion before they fully adapt to the new environment.

The Black Piranha will require a large space in the aquarium with plants for hiding.

Feed the fish regularly and ensure that the water is changed frequently as they are messy feeders.

Tank recommendations from experts suggest a large, wide and deep tank with a single Piranha in it. Water temperature of 73-79 degrees Fahrenheit with a pH level of 5.5 to 7.0.

As it’s shy and prone to startling with a cannibalistic nature if other fish are in its confines, putting other fish in the tank is not advised. Plants to hide behind are also recommended.

Growth is said to be slow with captive Black piranha rarely exceeding 35 cm.


The Black or Redeye Piranha is one of the most common species of the Piranha fish with their notable strong muscular bodies which exert a powerful bite which is estimated to be more than three times its body size.

Their jaws are very strong with triangular teeth that are arranged in a single row. The middle teeth are slightly raised to give a very strong bite.

Despite their strong bite, the fish is timid and shy and is less likely to attack as they are mostly scavengers that feed on dead animals.

They are known for their black and grey bodies with very bright eyes mostly red in colour. When this fish is kept in an aquarium, they prefer staying alone as they can attack other fish species in an aquarium.

Ensure that they are well feed as they can show signs of cannibalism.

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