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These Are 12 of the Largest Freshwater Fish on Earth

When we think of giant fish, most often we think of saltwater species. While it’s true that freshwater fish tend to be smaller, rivers and lakes can still harbor giants. The world is full of huge freshwater fish, and some of them are just as big as anything swimming out in the ocean. In fact, some of the largest freshwater fish are counted among the biggest fish anywhere, including saltwater species. In this article we’ll look at 12 of the largest freshwater fish in the world.

12 of the largest species of freshwater fish

1. Beluga Sturgeon

image: Geoff Parsons | Flickr | CC BY-SA
  • Scientific name: Huso huso
  • Largest on record: 23 feet, 7 inches long | 3,463 pounds
  • Lifespan: 100 years

The beluga sturgeon isn’t just the largest freshwater fish in the world, it’s the third largest of all the bony fish. In fact, some consider it the largest bony fish by weight. Beluga are famous for their roe (eggs), sold as beluga caviar, for which they’ve been hunted nearly to extinction.

It lives primarily in the basins around the Caspian and Black Sea. Sturgeon can live in both fresh and salt water, although they only spawn in freshwater. These fish are voracious predators, but they’re harmless to humans as they don’t have any teeth.

2. Alligator Gar

image: vhines200 | Flickr | CC BY-ND 2.0
  • Scientific name: Atractosteus spatula
  • Largest on record: 8 feet, 5 inches long | 327 pounds
  • Lifespan: 50 years

Alligator Gar are huge, mean-looking fish native to the southern U.S. These ancient fish have been around for millions of years, changing very little over that time. They got their name because, with their broad, tooth-filled jaws and long armored bodies they do bear a strong resemblance to alligators.

10 ft Alligator Gar in Mississippi in 1910 | original source unknown | David Foster | Flickr | CC 2.0 BY-ND

Alligator Gar were once hunted nearly to extinction because people were afraid of them and believed that they would wipe populations of popular game fish. These fears were entirely unfounded, because Alligator Gar have never attacked humans and they simply don’t eat enough to threaten populations of the native fish that evolved alongside them.

3. Arapaima

image: Jeff Kubina | Flickr | CC BY-SA 2.0
  • Scientific name: Arapaima gigas
  • Largest on record: 10 feet, 1 inch | 440 pounds
  • Lifespan: 20 years

These famous Amazonian fish have made an appearance in virtually every big fish documentary of the past twenty years. It’s easy to understand why: these fish are beautiful, sleek, and powerful. Their habit of leaping forcefully out of the water makes them exciting to watch, too.

Arapaima are able to breathe air when the oxygen levels in the water drop too low, which enables them to thrive in environments that would kill many other fish. Arapaima have been over fished in some areas, as they’re considered a delicacy. Fortunately, there are now farming operations raising arapaima for food so that the wild population doesn’t need to be targeted.

4. Mekong Giant Catfish

image: Lynn Chan | Flickr | CC BY 2.0
  • Scientific name: Pangasianodon gigas
  • Largest on record: 8 feet, 10 inches | 646 pounds
  • Lifespan: 60 years

These enormous fish are the largest purely freshwater fish in the world (Sturgeon are larger, but they inhabit both fresh and saltwater). They live mainly in Southeast Asia, particularly in the Mekong river and it’s tributaries. While their enormous size is certainly intimidating, they’re gentle giants with a diet consisting exclusively of microscopic plankton.

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Overfishing and habit loss have led to the Mekong Giant Catfish being critically endangered. Fishing for them in the wild is illegal, but the bans have not been as effective as hoped. These fish are popular for food, but fish of large size are becoming increasingly rare.

5. Paddlefish

credit: USFWS Fish and Aquatic Conservation
  • Scientific name: Polyodon spathula
  • Largest on record: 146 pounds, 11 ounces
  • Lifespan: 55 years

Paddlefish are North America’s strangest looking species, with wide, paddle-shaped noses and plump bodies. They’re native to all of the U.S. east of the Rockies, but are primarily found in the Mississippi River and it’s tributaries. These fish are filter feeders, using specialized gills to filter tiny plankton out of the water.

Paddlefish roe is sold as caviar, and is often considered a worthy alternative to expensive beluga caviar. Catching wild paddlefish for caviar is strictly controlled, but there are farms which raise them for caviar production. Paddlefish are a popular sport fish as well, because their large size and muscular bodies enable them to put up an incredible fight. They aren’t fished heavily in the wild, but dams and invasive Asian carp are threatening their population.

6. Giant Freshwater Stingray

image: Bernard DUPONT | Flickr | CC BY-SA 2.0
  • Scientific name: Urogymnus polylepis
  • Largest on record: 16.4 feet long | 1,300 pounds
  • Lifespan: 40 years

Native to Southeast Asia and Borneo, these enormous stingrays can be found in large, muddy rivers where they like to hide on the bottom, waiting for their prey. Despite their size, most of their food consists of small fish and invertebrates.

The 15 inch long stinging spine is the largest of any stingrays, and is capable of piercing bone. Luckily, it’s not an aggressive species and incidents of humans being stung are rare. In addition, these stingrays are very difficult to catch because of their size and their ability to dig themselves into the mud.

7. White Sturgeon

image: USFWS Fish and Aquatic Conservation
  • Scientific name: Acipenser transmontanus
  • Largest on record: 20 feet, |1,799 pounds
  • Lifespan:104 years

A relative of the larger beluga sturgeon, the White Sturgeon is native to the Western United States, where it is an extremely popular sport fish. It’s known for being a powerful fight and very hard to catch. Like the beluga, their roe is popular as caviar, and they were once nearly fished to extinction.

White sturgeon are a conservation success story, though, because the measure taken to preserve the species have allowed it to recover from over fishing and now the fish is no longer considered to be endangered.

8. Nile Perch

  • Scientific name: Lates niloticus
  • Largest on record: 6 feet, 7 inches | 440 pounds
  • Lifespan: 15 years

The Nile perch lives all through sub-Saharan Africa, favoring lakes and large rivers over smaller bodies of water. They’re voracious predators of other fish, and in places where they’ve been introduced (such as Lake Victoria) they become a dangerous invasive species.

Nile perch look a bit like an oversized bass, and they do share many characteristics- including their popularity as a sport fish. Nile perch are also one of the most economically important fish in East Africa.

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9. Wels Catfish

image: Bernard DUPONT | Flickr | CC BY-SA 2.0
  • Scientific name: Silurus glanis
  • Largest on record: 9 feet, 1 inch | 317 pounds
  • Lifespan: 60 years

Wels Catfish are famous for their size and their somewhat creepy appearance, as well as their ferocious predatory habits. It’s often thought that the Wels is responsible for a number of lake and river monster myths in its native range, which is central and eastern Europe and parts of western Asia.

It’s long, slender, snakelike body and aggressive feeding habits certainly lend themselves to monster stories. This fish has been seen grabbing birds from the river bank, and it’s conceivable that, in the past when they would’ve commonly grown larger than they do today, they would’ve taken even larger prey.

10. Piraiba Catfish

  • Scientific name: Brachyplatystoma filamentosum
  • Largest on record: 12 feet | 450 pounds
  • Lifespan: 25 years

This enormous fish is native to South America, where it is widely feared as a man-eater. It isn’t clear how true these rumors are, but it’s unlikely that these fish actively hunt live persons. They might, however, eat the bodies of people who die in the river, which is a common occurrence in many regions in the Amazon.

The Piraiba has a shark-like body and is an active and aggressive predator that will eat any fish it can fit into it’s mouth. It’s unusually fast and active for a catfish, and this, combined with its size, may have led to the belief that it’s a man-eater.

11. Taimen

  • Scientific name: Hucho taimen
  • Largest on record: 59 inches | 101 pounds
  • Lifespan: 55 years

The taimen, sometimes called the Siberian giant trout, is one of the largest members of the salmon family. Like many trout species, they’re entirely freshwater fish, and there are not oceanic populations. These large fish inhabit rivers and lakes in Russia and parts of Asia.

The taimen is becoming increasingly popular as a game fish, due its large size and the remote and scenic nature of its habitat. The largest confirmed taimen weight 101 pounds, but Chinese folklore tells of taimen in Kanas Lake that weigh over 4 tons. While fish of this size are unlikely, there are reports by researchers of 12 foot long taimen in Kalas lake, and tourists now flock to this remote location to try and spot the giant taimen.

12. Electric Eel

image: Brian Gratwicke | Flickr | CC BY 2.0
  • Scientific name: Electrophorus electricus
  • Largest on record: 8 feet long | 44 pounds
  • Lifespan: 10 to 15 years

Despite their name, electric eels actually aren’t eels, they just look like them. These large fish aren’t as heavy as some of the other fish we’ve listed, but they make up for it with their ability to generate lethal electric charges, up to 860 volts.

These fish live in the tropical rivers of South America, especially the Amazon and Orinoco rivers. They use their electrical abilities as defense against predators, as a tool for stunning and killing their prey, and even as a way to help them see in the murky water. They sense the world through their electrical fields.