11 Largest Freshwater Fish in the World

side profile of alligator gar fish snout in turquoise water

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The ocean isn't the only place where behemoth fish can be found. Hidden beneath the murky waters of our freshwater rivers and lakes are huge fish. While most freshwater fish are smaller than their counterparts in the salty ocean, there are some that can grow to impressive sizes. From bull sharks to giant stingrays, here are some of the largest freshwater fish in the world.

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Beluga

Beluga in a swimming among green plant life.

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The beluga is a species of sturgeon that inhabits portions of the Black Sea and the Caspian Sea. Because they continue to grow throughout their lifetime (which can be 100 years), the beluga might be the world's largest freshwater fish. Some have been found that are nearly 24 feet long and weigh over 3,500 pounds — numbers that also put them in contention for being the largest bony fish in the world by mass. The beluga hatches its eggs in freshwater rivers and then lives its adult life in saltwater, returning upriver to spawn. The beluga is also critically endangered, with a decreasing population.

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Mekong Giant Catfish

Profile of a Mekong giant catfish in water.

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Many species of catfish can grow to mammoth sizes, but none compare to the Mekong giant catfish of Southeast Asia. Capable of growing up to 10 feet long and weighing over 650 pounds, their size makes them a prized catch, and these giant catfish have been nearly fished to extinction. Though they are now protected, they are likely to remain critically endangered due to the construction of upstream dams on the Mekong River.

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Alligator Gar

A pair of large alligator gar swimming in opposite directions in clear water.

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Due to a dual row of large teeth and a snout like an alligator, these carnivorous fish are able to live in fresh and saltwater. Measuring as long as 10 feet and weighing as much as 350 pounds, alligator gars are the second largest fish in North America. They live up to 50 years and have few natural predators. Found in the lower Mississippi River basin and in the waters of the Gulf Coast states, these fish tend to swim near the surface or among reeds where they can ambush prey.

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Arapaima

A forward facing Arapaima swimming in a lake with green plants below.

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Found in the Amazon River, these giant fish are as ancient as they are large. Also known as pirarucu in Brazil and paiche in Peru, arapaima have been around since the Miocene and are considered living fossils. Once capable of growing to a length of 10 feet and a weight of 300 pounds, due to over-fishing, arapaima now reach about 6 feet in length and 275 pounds. These fish are able to breathe air and can survive up to 24 hours outside the water.

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Giant Freshwater Stingray

A giant freshwater stingray on the sandy bottom of a river.

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One of the largest freshwater species in the world, the giant stingray was first identified by scientists in the 1990s. These freshwater fish can grow to massive sizes, with some weighing in excess of 1,300 pounds and measuring nearly 15 feet across. Found in the rivers of Southeast Asia, they have tails that measure up to 15 inches long with a serrated spike that is capable of piercing bone and injecting venom. Unfortunately, the giant freshwater stingray is endangered due to fishing and habitat loss.

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Paddlefish

An American paddlefish on the bottom of a river surrounded by other fish.

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Easily recognizable by their paddle-shaped snout, these river giants are harmless filter-feeders, opening their mouths to capture zooplankton. There are two extant species of these creatures, the Chinese paddlefish and the American paddlefish. Unfortunately the Chinese paddlefish, which inhabits the Yangtze River, is critically endangered and possibly extinct. The larger of the two species, measuring as long as 10 feet, the Chinese paddlfish are threatened due to over-harvesting and habitat loss. American paddlefish, which are listed as vulnerable, inhabit the Mississippi River basin and once inhabited the Great Lakes in Canada as well. They can grow to lengths of 8 feet and weigh up to 150 pounds.

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Giant Barb

Giant Siamese carp in clear blue water.

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Carp of all varieties can grow to formidable sizes, but none are as large as the giant barb found in Southeast Asia. This species of carp regularly grows to 10 feet in length and adults are rarely found under 5 feet. Although they grow to such large sizes, giant barbs are harmless; they prefer to eat small organisms like algae, phytoplankton, and, occasionally, fruit. The giant barb is critically endangered due to over-fishing and habitat loss.

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White Sturgeon

A white sturgeon swimming right above the sea floor.

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Easily the largest freshwater fish in North America, the white sturgeon can grow to 12 to 20 feet in length and can weigh nearly one ton. Found along the West Coast of North America, and as far north as the Aleutian Islands, white sturgeon inhabit rivers, streams, estuaries, and the sea. They migrate upriver to spawn and have a lifespan of 80 to 100 years. Due to their size, white sturgeon are a popular target for fishermen, and while not federally listed, they are categorized as a state Species of Special Concern in California.

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Nile Perch

Large scaled Nile Perch swims underwater with rocky background

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Native to the tropical rivers and lakes of Africa, the Nile perch is Africa's largest freshwater fish. Reaching a maximum length of 6 feet, these fish typically range from two and a half to three and a half feet. Due to their popularity among fishermen, the Nile perch has been introduced to many non-native lakes and has become a dangerous invasive species. This has been especially tragic in Lake Victoria, where more than 200 native species have been driven to extinction due to the introduction of the Nile perch.

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Siberian Taimen

A fisherman in a lake holding a taimen above the water.

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The Siberian taimen, found in freshwater rivers and lakes of Russia, Mongolia, and Central Asia, is the largest species in the salmon family. They are long-lived and slow growing, reaching lengths of up to 6 feet at maturity. In addition to fish, Siberian taimen feed on creatures like rodents and birds. The Siberian taimen is listed as vulnerable with a decreasing population due to pollution and sport fishing.

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Bull Sharks

A bull shark near the bottom of a waterway with rocks below and small fish above.

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Bull sharks are a coastal and freshwater shark that spend their time in tropical and subtropical bodies of water across the world. They can reach lengths of over 11 feet, though most are 6 to seven and a half feet long. Mainly found in shallow water, bull sharks are the only species of sharks that can endure extended periods in freshwater. An aggressive species, bull sharks are known to attack humans. They are near threatened due to human interaction and development near their habitats.