Pacu Fish: Types, habitats, characteristics and more…

Pacu fish are interesting and very tasty fish very similar to Piranhas. These fish native to the Amazonian have their own myths and legends and really worth learning about them..

The Pacu Fish’ History

The history of this species goes back many years ago, when the Indians discovered them within the Amazon area and a total stir was unleashed by their peculiar traits.

Many natives believe that Pacu fish are more carnivorous than piranhas and many nicknamed as » ball-cutters”» because there have been several unconfirmed testimonies of such a situation. According to the criteria of many scientists, their anatomy goes back many centuries ago, and most of them agree that the Pacu fish can be a surviving species of dinosaurs’ age.

Their anatomical traits also indicate that it is one of the few species that have not undergone many changes over the years, probably because they have kept their food habits constant. The Pacu fish’s peculiarity to which many experts refer is that they don’thave a pointed denture like that of other fish, but on the contrary this species is unique among the others because their teeth simulate the same as that of the human beings.

The Beginning of the Legend

The Pacu fish’ legend began in Papua New Guinea when several specimens attacked two fishermen. It was there when the press popularized the denomination of “ball- cutters” for Pacu Fish.

However, the experts, calmed-down the swimmers about the dangers of these fish. The fact that they are omnivores doesn’t mean that they attack human beings and will only do so in the event that they are hungry and have no more food nearby. They can also eat other fish and invertebrate organisms.

In spite of the suspicion that their appearance arouses, halfway between a great piranha and a human denture, the Pacu is a very appreciated species in South America.

Although first known for its economic value, since it’s  a tasty fish served in restaurants and very appreciated, this species is best known as protagonist of many stories by its appearance and habits, reasons for which have been shown in several TV Sensational documentaries.

The incredible frontal resemblance of their teeth to that of human beings makes it frequent to see photos of this species, «smiling» or in dentists’ advertisements. Pacus are legendary fish also by the supposed painful attacks to humans’ testicles.

Papua Guinea

In Papua New Guinea, where the species has been introduced, pacu fish are known as «the Ball Cutters», because according to some residents of the country, in 2001 attacked several fishermen who died bled in the water after suffering serious bites on their testicles. Populations of other fish, aquatic birds, amphibians and reptiles such as alligators or crocodiles are thought to have decreased, attacking young specimens or the offspring.

It seems that these attacks are motivated by hunger and are more common in areas where they have been introduced and there is overpopulation of Pacu Fish or they just don’t find the food.

Some culinary specialists simply love and recommend these fish, as for example the species Piaractus Mesopotamicus which is highly appreciated for its soft and soft flesh. In addition, its meat is rich in fatty acids Omega 3 and 6, so it has a huge nutritional value.

pacu fish: papua guinea

The Pacu Fish’ Main Characteristics

Pacus are a big family of freshwater fish quite related to the Piranhas. However, they aren’t carnivorous fish but herbivores ones and very peaceful. Thus, their nickname of “ball-cutters” doesn’t seem to be that real.

Pacus’ big size makes them a good choice only for experienced aquarists who can provide their required care. An adult Pacu can be over 30 inches long and will need to be kept in a pond or an enormous tank.

A very distinctive and even weird trait of this species is given by their skill to develop a sort of personality as they become adults and sometimes recognize their owners. Such an aspect makes them a popular choice among aquaria enthusiasts.

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Where do Pacu Fish Inhabit?

Pacu fish are freshwater fish from tropical climate native to the Amazonia. They have also been seen at the Florida coasts’ seas and in waters as cold as those of the Seine in Paris, those of Lake Michigan, in New Jersey or the waters of Sweden.

Types of Pacu Fishes

There are several types of pacu fish with specific characteristics that differentiate them from each other, so it is important to know each of them.

Myleus pacu

Known in spanish as pacú, pacupeba, eatau, is a freshwater fish belonging to the Characid family, native to the fresh waters of South America, mainly the Amazonian rivers. The Pacupeba, tends to prefer tropical habitats, with water temperatures that range between 22 and 28 ° C.

Their dorsal area is dark gray and the ventral whitish yellow. In their natural environment they can grow up to 90 cm in total length and weigh around 30 kg.  The young specimens up to approx. 40 days of age have a black spot on both sides, which gradually disappears with age. Their gills have numerous lamellae that work as filters, in this way they take advantage of the numerous organisms (zooplankton) present in the water.

During their adult stage Pacus present a marked sexual dimorphism since the males develop a larger dorsal fin and have a greater coloring. Moreover, females are larger than males and more robust and rounded. They can weigh up to 55 pounds (25 kg) and reproduce during the winter migrating to the smaller streams to spawn.

Other Traits

The Pacupeba, is highly appreciated for its flavor, which is why it has been introduced in other parts of the world. They live in the great rivers’ middle section and migrate to spawn to streams and gravel bottoms. The populations usually make-up schools of fish and their bites are very painful.

Myleus pacu is an omnivorous fish that also feeds on fruits, plants, algae and seeds. When they are adults, they preferentially feed on Podostemaceae (plants of the genus Lacis and less frequently of the genus Caladium).

They have a very developed smell sense and are attracted to the smell of animal fat, such as that present in blood, urine, mollusks, insects, crustaceans or in sweat.


This is a gregarious and quite peaceful fish for its size, although not suitable for a community aquarium. Larger adults can be solitary. It is common to see them biting each other’s ears that leave their fins marked. They are very resistant to diseases and swim in the aquarium middle- area. If you want to keep them when they become adults you will need a big aquarium of 500L.


It hasn’t been achieved in aquariums probably because of their size, but is in fish farms. In Nature they migrate to counter-current for spawning to reach flooded plain areas, where spawning occurs between December and April. The eggs are green, between 0.9 and 1 mm in diameter and their development is very fast. at 24 hours at a temperature of 28 º C.

Feeding Habits

The Pacupeba, Is an aggressive eater that feeds on algae, parts of aquatic plants, both fresh and decomposing, zooplankton, terrestrial insects and others.

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Small-Scaled Pacu  (Piaractus Mesopotamicus)

Like the other species, this Pacu fish is originally from the freshwater but from the rivers of Paraguay and Paraná. It has a sturdy and flattened body where a single color prevails. They can reach up to about 45 cm in length and weigh about 20 kilograms.

Body Color

It is of grey or silver color with a yellowish dorsal area and a completely whitish belly. Moreover, small black spots can be observed on the edges of their fins.

Feeding Habits

Piaractus Mesopotamicus is an omnivore creature that eats almost everything from aquatic plants to crustaceans, snails, fish and fruits that fall from the coastal trees.


This is pacific Fish that swims in shoals that like to stay in a tank with free swimming space. It likes to bite the wiring of the electrical appliances of our tank (filters, etc.) so you should be cautious when such thing happens. In the same way using protections for the thermostats is totally recommended because they are very curious and somewhat abrupt.

Whenever you put your hands in the tank you have to be cautious since their bite is quite powerful and could cause us an unfortunate loss of muscle tissue or a finger. This occurs especially when the specimen is poorly fed or lacks adequate space, but a curious specimen can bite a confusing finger with a fruit. Their life expectancy ranges between 25 and 30 years. .


The reproductive male must be placed in a 300 liters aquarium with good vegetation and a plant that reaches the surface. It must also have plants and other floating objects that will be useful for the male to build the nest.

The Aquarium must be kept at 28 °c and the water characteristics must be optimal. When the aquarium is ready, you can place there the male that has previously been kept separate from the female for the spawning beginning.

If all has turned out well the fingerlings will hatch at 24-48 hours. They should be fed with infusions and rotifers and then with Daphnia and artemia freshly hatched. After 7 days they will accept powdered flakes.

Tambaqui (Colossoma macropomum)

They belong to the Serrasalminae subfamily, being native from the Orinoco basin and the Amazon. The Tambaqui is a relatively large fish, widely distributed from the Orinoco throughout the Amazon Basin, which has represented for many years an excellent, abundant and desired product of river fishing, with appreciable abundance in local markets and some other important cities in the country (Venezuela). Among the most important species of Tambaqui we can mention the following.

The Black Tambaqui (Colossoma macropomum)

The Chera or Black Pacú is a fish native  to the Orinoco basin, from where it was distributed to the Amazon. It has a migratory behavior and it moves many kilometers upstream, during the summer.

Its reproduction is carried out every year during winter: it leaves its fertilized eggs in the margin of the rivers and in newly flooded areas, where the wild fry grow. There is not sexual dimorphism during their young hood and only reache sexual maturity at age 3.

Adults Black Pacus measure from 70 to 120 centimeters and up to 35 kilograms of weight. They are grey to black and their pectoral fins are small and black. They mainly feed on micro planktonic crustaceans, fruits, algae and larvae.

The white cachama: (Piaractus brachypomus),

Commonly also called white pacú, mbiraí or flatfish, it belongs to the Characidae family native to the Amazon. It reaches around 88 centimeters in lengthand 20 kilograms in weight with silver and reddish fins proliferating in waters with temperatures between 23 and 27 º C.  The white cachama feeds on fallen plants, fruits, larvae and insects and its flesh is quite coveted and being raised in ponds now a days.

The Tambacu or Cachamoto ( Colossoma X Piaractus,)

It can reach a total length of more than 100 cm and a weight of 40 kg. It is a hybrid species, which has been produced from the crossing of the Black pacu which has a great growing potential.

The Tambacu has great capacity to adapt to the different environmental conditions, and they are resistant to manipulation and diseases, being not very demanding in terms of water quality.

It also has a big size,  (up to (1.1 m)  and a fast growth. Thanks to this type of crossing, Tambacu has a dark golden color. In terms of feeding habits, this omnivorous species, that eats fruits that fall into the water, such Mangoes, guavas and several aquatic invertebrates.

As for its reproduction, the tambacú is able to produce eggs and semen, although it’s sterile. Thus, females of black cachamas  and Black males pacus are crossed  to obtain Tambacus’ fingerlins.


Cooking Pacu Fish

Mix lemon juice and olive oil in a bowl. Add pacu fish ribs and coat evenly. Place ribs on a baking sheet seasoning them with salt and pepper.
Then you can grill the ribs over medium high heat during 3 min. Flip and brush sauce gently on skin as glaze. Continue grilling on low heat until properly cooked. Barbecue sauce and lemon wedges will be the perfect table-mates for this species.

Enjoy your meal


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