Discover everything about the giant pirarucu: an almost invincible fish


Discover everything about the giant pirarucu: an almost invincible fish

The “pirarucu” or “arapaima” is the largest freshwater fish in America and is among the largest in the world. It is possible to find them in the Amazon basin and other South American rivers. It can measure more than 3 meters and weigh up to approximately 250 kilos; but its large size is just one of the amazing characteristics of this fish.
It spends half of the year swimming among trees that are surrounded by large expanses of water resulting from the rains and thaws of the Andes Mountains. During droughts, when the flow of the rivers decreases, they can even end up buried in the mud, waiting for the next rainy season. How is this possible?

Although it seems impossible, this fish can breathe air out of the water thanks to a highly developed swim bladder that works like a lung, which makes the pirarucu a true survivor of climatic adversity.

This forces him to come to the surface and that’s when the opportunity to be trapped by the only predator against which this giant of the river can not defend himself appears: Man.


Their large size of the arapaima gigas – its scientific name – in addition to its delicious flavor, make it one of the main attractions for sport fishing. It is this that has led the pirarucu to become an endangered species.

Another interesting fact that is related to the skin of the pirarucu, is that

it acts as a shell, similar to an armored shield, despite measuring less than a millimeter thick. This has a very hard consistency due to the minerals that make it up, which prevents them from being damaged by the fangs of some predators, as is the case with piranhas.

Its skin is also composed of a second layer that bends thickness and flexibility, composed of sheets of collagen, interlaced and able to resist various embedments. Align according to the pressure to which they are subjected, which protects their internal organs, making the piraracu practically invincible.

Arapaima 2

Traditionally, they were fished with spears, but overexploitation has even led to fishing with nets, thus preying not only on pirarucu but also on those who cross their path.

To improve its critical situation, protection measures have been proposed, increasing the population of piracuru to an estimated 5,000 wild specimens. These are excellent news, since in comparison to 2002 the population was estimated at 800. However, breeding in captivity, this is only to supply local markets and restaurants. Being a fish that grows rapidly (up to 10 kilos per year) and does not need many conditions to develop, reaching sexual maturity at 5 years, it is relatively easy to reproduce under these conditions. However, this has only allowed a cessation of fishing which does not solve the damage caused to the ecosystem. The low extraction of these from their habitat has contributed to the natural restoration of the population. Even so, these measures are far from being enough to correct the damage caused. It is expected that these initiatives aim at the breeding and subsequent release of these along the river network of the Amazon basin in order to equal or overcome the native sifra before the intervention of man.

This voracious fish is carnivorous. His diet consists mainly of fish, but if he is hungry, he will try to eat anything that fits in his mouth. This includes small, mammals, amphibians, crustaceans and birds. Although it can feed underwater, it is normal to look for its prey on the surface, attacking distracted fish or unfortunate chicks that have fallen from their nest.

Despite its enormous size; its brown colors and slow movements make the pirarucu a very effective predator, camouflaging perfectly with the waters rich in organic material of the rivers they inhabit. This allows him not to be warned by his prey.

This feature not only serves to feed you but also uses it as a measure of protection. the piracuru nests in the bottom of the river, to protect potential predators of its young. Before birth he even keeps them in his mouth to keep them safe from any predator. Another curiosity regarding the reproductive and breeding habits of paracuru is related to a behavior very similar to that of mammals. in the local culture it is said that he would nurse his young, even though in reality this is not exactly so. Both the father and the mother have the ability to produce a substance similar to milk for the purpose of feeding you. This secretion from the head of the fish has a high nutritional content, rich in hormones and proteins, which serves as food while they are too small to feed themselves.

As you can see, its large size is actually the least of its curiosities. If you look closely, in the Yasuni National Park you will have the opportunity to meet face to face with these specimens of prehistoric appearance and imposing size: a must for lovers of exotic animals!

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