River Monsters: Discover the Biggest Fish in the Mississippi River

Flowing 2,350 miles south, from Lake Itasca in Minnesota, the Mississippi River bisects the continental United States, as it passes through Minneapolis, St. Louis, Memphis, and New Orleans before emptying into the Gulf of Mexico. According to the National Park Service, there are more than 120 fish species inhabiting the Mississippi River. Fish in the Mississippi River range dramatically in size, from tiny minnows to huge, prehistoric species. Continue reading to discover 10 of the biggest fish in the Mississippi River.

10. American Eel

The American eel (Anguilla rostrata) is a long fish. Females range from 2 to 3 feet long and weigh 1 to 3 pounds. American eels have a remarkable migration. They hatch in the Sargasso Sea and then ride the currents to the brackish waters in the Gulf of Mexico, where the Mississippi empties. The males, which average 1.5 feet long, remain in brackish waters, while the females start the long journey up the Mississippi, making homes along the way in rivers and streams, with some reaching Minnesota.

9. Channel Catfish

Channel catfish (Ictalurus punctatus) are among the smaller catfish found in the Mississippi, but they are also a favorite of anglers. With their cat-like whiskers, they are easy to identify. Most channel catfish are 2 to 4 pounds and measure 1.5 to 2.5 feet long. The largest channel catfish on record weighed 58 pounds and measured 3.9 feet long. They are nocturnal and feed on other Mississippi River fish, such as the American gizzard shad (Dorosoma cepedianum).

8. Blue Catfish

The largest catfish in North America is the blue catfish. They have a bluish tint with a white belly. Most blue catfish weigh 3 to 40 pounds and measure 1.6 to 3.75 feet long. The largest blue catfish caught in the Mississippi River weighed 131 pounds and measured 4.72 feet long. However, the largest specimen ever caught was in Lake Kerr, weighing 143 pounds and measuring 4.75 feet in length.

7. Flathead Catfish

These catfish have the same whiskers as the channel cats but are slightly larger. Flathead catfish (Pylodictis olivaris) average 1.25 to 3.75 feet in length and 20 to 40 pounds in weight. The largest one caught in the Mississippi River was 89.8 pounds, caught in the Yazoo River, a tributary of the Mississippi, in 2023.

6. Striped Bass

Many anglers enjoy fishing for bass. Striped bass (Morone saxatilis), commonly called stripers, are the largest of the bass species. They are born in freshwater but typically migrate to saltwater. The average striper weighs 20 to 40 pounds, and the largest specimen recorded weighed 81 pounds 14 ounces. Stripers average 1.6 to 2.9 feet in length.

5. Longnose Gar

Longnose gar (Lepisosteus osseus) weigh 20 to 40 pounds and measure 3 to 5 feet in length, although much of that length is due to their long nose. They have long, slender bodies covered in scales. Their long, narrow snout is lined with tiny, sharp teeth.

4. Bighead Carp

Bighead carp (Hypophthalmichthys nobilis) are filter feeders that consume phytoplankton, detritus, and zooplankton. On average, they measure 2 to 4 feet long and weigh approximately 40 pounds. The largest recorded specimen was caught in Oklahoma in 2025, weighing 118 pounds 10 ounces and measuring nearly 5 feet long. Their eyes are located lower on the head, and their bodies are covered in silvery scales.

3. Paddlefish

Members of the Polyodontidae family, commonly known as paddlefish, have long, paddle-shaped snouts. They are filter feeders, and their long snouts serve as sensory organs used to locate zooplankton and other tiny animals. American paddlefish (Polyodon spathula) average 4.9 feet in length and 60 pounds. The largest American paddlefish was caught in Lake of the Ozarks and weighed 164 pounds, 13 ounces.

2. Alligator Gar

Alligator gar (Atractosteus spatula) on average measure 4 to 6 feet long and weigh approximately 100 to 160 pounds. The largest alligator gar caught in the Mississippi River weighed 327 pounds and measured 8 feet 5 1/2 inches. These fish are opportunistic, nocturnal ambush predators that primarily feed on fish. Their diet also includes waterfowl, turtles, and some birds.

1. Gulf Sturgeon

The biggest fish in the Mississippi River is the gulf sturgeon (Acipenser desotoi). Gulf sturgeon can be found in both freshwater and saltwater, depending on the time of year. They are covered in five scutes, bony plates that line their back. Gulf sturgeon typically measure 5 to 6 feet in length and weigh 100 to 200 pounds. The largest specimens can grow up to 9 feet and weigh over 300 pounds. While visually indistinguishable from Atlantic sturgeon (Acipenser oxyrinchus), gulf sturgeon are no longer considered a subspecies of Atlantic sturgeon.