The 5 Largest Freshwater Fish In The World
The fauna of the world’s rivers and lakes includes fish whose size easily exceeds that of an ordinary human. Although you may generally be used to seeing harmless small animals in aquatic ecosystems, the world’s largest freshwater fish can be perplexing if you ever come across them.
These freshwater monsters almost always destroy any prey within their reach. Due to this same power and enormous size, they are the favorite target for fishermen and species traffickers. Below, you will find 5 specimens that fit within the largest in the world.
1. Catfish
This huge fish ( Silurus glanis ) hails from central Europe and Southeast Asia. It belongs to the Siluridae family and is characterized by being a solitary fish, by presenting very long beards and a great appetite. Their diet is based on other small fish, waterfowl, and crustaceans.
Physically, this animal is elongated and its body is laterally compressed. Its skin has no scales, as it is covered with a mucus that allows it to tolerate widely the contamination of the rivers and dams where it lives. Its anal fin is the longest and is located between the anal orifice and the caudal fin.
They can reach a size between 3 and 4 meters in length, in addition to weighing up to 300 kilograms. Currently, it is not in danger of extinction, as it has been introduced in some European countries such as Spain and Italy. Sport hunting has caused catfish to affect the ecosystems where it has been released, by feeding on endemic species.
2. Piraiba
This is undoubtedly one of the largest fish in the Amazon. The piraiba ( Brachyplatystoma filamentosum ) can weigh more than 200 kilos and measure more than 3.5 meters in length. Its main attribute is its mouth, which measures almost 40 centimeters: with it it engulfs other fish, amphibians, birds, snakes and small mammals.
Its body is characterized by being long and its head slightly flattened or depressed, like common-sized catfish. Similarly, it has 3 pairs of barbels. It prefers deep waters, with a maximum of 30 meters and a minimum of 1 meter. Overfishing has put this fish in danger of extinction, due to the excellent quality of its meat.
3. Giant stingray
The giant manta ray – Urogymnus polylepis , also known by the minor synonym Himantura chaophraya – is one of the largest freshwater fish in the world. Its main habitat is the rivers of Southeast Asia, such as the Chao, Phraya and Mekong rivers.
Its size is 2 meters wide and 5 meters long, approximately. It can weigh up to 600 kilos and, due to lack of information, it has not been classified as the largest freshwater species. Poaching, the deterioration of its habitat and massive hunting have led the International Union for Conservation of Nature to consider it in danger of extinction.
The giant manta ray feeds on fish and crustaceans from the bottom of rivers, as it rarely comes close to the shore or the surface. Its reproduction is of the viviparous type and, after gestation, the female gives birth to litters of 3 to 5 young. It is important not to confuse it with the giant marine manta ray ( Mobula birostris ), which does not have venom.
4. Sturgeon
This fish ( Acipenser sturio ) belongs to the Acipenseridae family and has inhabited the rivers of planet Earth for many centuries – 250 million years, to be exact. The taxon includes almost 20 species and the largest recorded specimen weighed almost 800 kilograms and measured 6 meters.
Sturgeon eggs are used for caviar, although only 12 or 16% of the female’s weight is made up of this product. The northern hemisphere is its favorite habitat, since the fresh waters of North America, France and Spain are the places where this huge fish reproduces and lays its eggs.
Their reproduction takes place after 8 years of age in the case of males and after 13 years in the case of females. The number of eggs is generally considered to range between 300,000 and 2 million, which mature in a month at about 17 degrees Celsius. This animal feeds on crustaceans and mollusks, as well as worms.
The youngest sturgeons stay for more than a year near the mouth of rivers. Today, like many other species of the world’s largest freshwater fish, it is critically endangered. The causes are poaching and the reduction of the flow of the rivers where they usually live.
5. Arapaima
The arapaima or pirarucú ( Arapaima gigas ) takes second place among the largest freshwater fish in the world. With a weight of 250 kilograms and a length of 3 meters, this enormous fish inhabits the waters of the Amazon, Madre de Dios and Beni rivers in South America.
Its body has quite large and sharp scales. As it exists in poorly oxygenated waters, it must rise to the surface to take some bites of air, when its gills fail to capture the necessary oxygen. It feeds on other smaller fish, reptiles, amphibians, and small birds that fall into the water.
Curiously, arapaimas prefer the sands of rivers to lay their eggs, about 20 centimeters deep. Currently, this species is in danger of extinction, due to the great persecution and hunting that was generated by the enormous commercial value of its meat.
As you could see, the world is full of animals whose size can surprise anyone. Rivers and lakes hold great secrets and huge fish that, for centuries, have evolved to adapt to their habitat. The lizard peje ( Lepisosteiformes ) and the tiger fish ( Hydrocynus goliath ) are other examples of the enormous fish that inhabit the rivers of the planet.
