River Monsters: Discover the Largest Fish in the Potomac River

Written by Colby Maxwell
Updated: September 19, 2023
© iStock.com/Ekaterina Aleshinskaya
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Infographic about the Potomac River
The Potomac River is iconic in US history and life in Washington, DC.

The Potomac River is one of the most important rivers in the eastern United States. Beginning in the Potomac Highlands of West Virginia and flowing into the Chesapeake bay 405 miles east, this waterway provides power, transportation, and more to the 5 million people within its watershed. Even more, the national capital of Washington D.C. sits along its shores before it heads into the Atlantic.

4 Largest Fish in the Potomac River
These four fish are prized by anglers because of their great size.

Although millions of people live along its shores, the wildlife under the water is just as diverse! Today, we are going to explore the largest fish in the Potomac. These River Monsters aren’t just myths!

What are the largest Fish in the Potomac River?

River Monsters: Discover the Largest Fish in the Potomac River
Three potential Potomac River Monsters are the blue catfish, the sturgeon, and the muskie.

©Vladimir Wrangel/Shutterstock.com

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The three largest species of fish in the Potomac River are the blue catfish, sturgeon, and muskie.

The Potomac is a relatively large river that ranks 5th in the eastern US and 21st in the US as a whole. Although it may be well developed, there are still some mysterious river monsters living in its waters.

The largest river monster that one is likely to find in the Potomac is the blue catfish. These catfish live all over the United States and can get incredibly large. Blue catfish can loom quite scary, especially when they weigh as much as a human.

A second, much rarer, contender for the largest fish in the Potomac is the sturgeon. There are two species of sturgeon that can technically be found in the river, the Atlantic and shortnose sturgeon, although they are both extremely uncommon.

A third potential river monster is the muskie (muskellunge). These large, predatory fish don’t grow as large as a blue catfish or a sturgeon, but they are still quite formidable.

Let’s learn about each of these fish in a little more detail below.

1. Blue Catfish

River Monsters: Discover the Largest Fish in the Potomac River
Blue catfish is a common giant fish in the Potomac.

©Billy Ogle/Flickr – License

The largest and most common giant fish in the Potomac is easily the blue catfish. These massive fish are the largest catfish species in the United States and the largest species of fish in the Potomac. On average, blue catfish measure between 25 and 46 inches and weigh up to 10 lbs, but they can get much larger. The largest blue catfish ever caught was 65 inches long and weighed 150 lbs.

Although these fish are native to North America, they are not native to the Potomac. They were first introduced in the 1970s when fisheries began stocking tributaries in Virginia to create recreational areas for tourists. Since then, these invasive fish have spread through the entire Chesapeake system and are considered a pest.

2. Atlantic Sturgeon

River Monsters: Discover the Largest Fish in the Potomac River
Atlantic sturgeon is one of the largest fish that can be found in the Potomac River.


Although the blue catfish is the most common river monster in the Potomac, the sturgeon is much larger and more mysterious. Two species of sturgeon can be found in the Potomac, the Atlantic and shortnose sturgeon.

The Atlantic sturgeon is one of the largest fish in the United States. They can grow over 14 feet long and weigh up to 800 lbs, easily surpassing the blue catfish as the largest fish in the Potomac. The only issue is that Atlantic sturgeon were basically fished to extinction in most of the river and are rarely if ever, found there. In the 1890s, hundreds of thousands of pounds of sturgeon were harvested annually, destroying populations. By 1928, Atlantic sturgeon were extremely rare through the Potomac, although it was once part of their historic range. Repopulation efforts are currently underway.

3. Shortnose Sturgeon

A big Short nose sturgeon
Shortnose sturgeon are mostly found in the Carolinas and Florida.
Image: pixel creator, Shutterstock

©pixel creator/Shutterstock.com

The shortnose sturgeon isn’t as large as the Atlantic sturgeon, generally growing to 3.5 feet and weighing 15 lbs at a max. Like the Atlantic sturgeon, the shortnose sturgeon was overfished in the Potomac and the surrounding region. Now, these fish are generally found in the southern states, namely the Carolinas and Florida. Still, there are still small mid-Atlantic populations still around today.

4. Muskie

River Monsters: Discover the Largest Fish in the Potomac River
The muskie is a large predatory fish that resemble a pike.

©M Huston/Shutterstock.com

Muskellunge, usually shortened to muskie, is a predatory fish that lives all over North America. They are similar to pike in their appearance and behavior, although they are distinct species. Muskies are usually between 28-48 inches long and weigh up to 36 lbs. The largest individuals ever caught have been over feet and weighed over 70 lbs, however. Muskies aren’t as large as blue catfish or sturgeon, but their predatory nature most definitely qualifies them as river monsters!

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About the Author

Colby is a freelance writer from Charlotte, North Carolina. When he isn't distracted by his backyard birdfeeder, you can find him camping, exploring, and telling everyone around him about what he's recently learned. There's a whole world to learn about and Colby is content to spend his life learning as much as he can about it!

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