Updated: Oct 25, 2022
By David Graham: 4-6-2022
On the global scale of Freshwater Fish - every continent and country has its handful of unique 'monster fish'. When we think of giant freshwater fish it's easy to look at South America - with the massive Arapaima, and about a half dozen species of catfish that can grow and exceed hundreds of pounds... European countries boasting the massive Wels Catfish, carp, and pike... Asia with the giant Siamese Carp, freshwater stingray, and catfish of the Mekong river systems.. Africa and its enormous Nile Perch and Goliath Tigerfish - just to name a few.
But I want to assemble North America's roster... where our own lineup of freshwater beasts grow to respectable and competitive statures on the global landscape of freshwater monsters. Here - I am putting together our top 10 - North American 'Monster Fish'.
The White Sturgeon (Acipenser transmontanus) to 500+ lb
Arguably among the largest freshwater fish on the face of the earth - the White Sturgeon has the propensity to reach in excess of 12 feet long and 500+ pounds... and there are older records of fish pushing 1,000 pounds. This prehistoric giant is native to the Pacific Northwest region of North America where its status as a true freshwater fish is often debated - as they are naturally an anadromous migratory fish species that spends some of its life in the ocean, migrating in and out of river systems. Still, there are landlocked populations of White Sturgeon in Idaho, Montana, California, Oregon to name a few that exist solely in freshwater. The White Sturgeon is primarily a bottom feeder that seeks out most available food sources like mollusks, crustaceans, fish, and worms.
2. Alligator Gar (Atractosteus spatula) to 300+ lb
There are few fish that swim anywhere on planet earth that may invoke a more primal reaction than the Alligator Gar. North America's largest predatory species is another prehistoric giant that immediately engages the conscience of anyone who should gaze upon it. With fossil records dating back some 150 million years - the present day Alligator Gar is actually the largest known version of the species... with the propensity to reach upwards of 8-9 feet in length and over 300 pounds. This armor clad monster leaves a lot to the imagination - sporting a reptilian set of jaws lined with two rows of impressive teeth. The Alligator Gar is an active predator, but its primary niche in the environment is to take the slow and unwary species... eliminating weak genetics and potential spread of disease. Although one look at this fish leaves you imagining it simply eating everything in its path, the Alligator Gar is the quintessential 'gentle giant' and is very subdued in its environment... sustaining its massive size on irregular and infrequent meals for the most part. Today their stronghold is in the rivers of East Texas and Louisiana - but it was once prevalent along the Gulf Coastal region of the Southeastern United States.
3. Lake Sturgeon (Acipenser fulvescens) to 200-300 pounds~
The smaller cousin of the aforementioned White Sturgeon, Lake Sturgeon grow to a very respectable size themselves. Out of the shadow of their big cousins... we see a fish that has been documented in excess of 250 pounds, the largest recorded being 310 pounds.. and while this is no ordinary feat - Lake Sturgeon are frequently caught at or near that 100 pound threshold of 'giants'. This may be the most widely distributed sturgeon species on the continent, found in the St. Lawrence river, Hudson Bay, Great Lakes, and Mississippi River watersheds - The Lake Sturgeon's range encompasses 5 Canadian provinces and 24 states. Like other sturgeons - the lake sturgeon relies heavily on other senses to compensate for its poor eyesight. A set of 'barbels' like whiskers sit below its snout to scan the bottom for forage items like small fish, insect larvae, crustaceans and more.
4. Paddlefish (Polyodon spathula) 170-200 pounds~
What might be the strangest fish on the list is the American Paddlefish. Known regionally as Spoonbill, spoonbill catfish, and most commonly paddlefish - this is yet another one of North America's treasured prehistoric relics.... dating back some 125 million years. The unique paddlefish can grow to enormous proportions - reaching upwards of 200 pounds in some cases. Interestingly, this behemoth fish sustains itself on a tiny food source. Swimming, mouth agape, primarily filter feeding on tiny zooplankton. The paddle fish uses its ‘paddle’ which is actually a highly developed rostrum to detect its micro food source. Still, paddlefish have been known to feed on small insects, larvae, and even small fish. Because of this, they are occasionally captured on small fish patterns or grubs - but the majority of paddlefish are intentionally ‘snagged’ using large treble hooks.
5. Blue Catfish (Ictalurus furcatus) - 150 pounds~
Our largest catfish species - the Blue Catfish is a true monster. This gorilla of a fish has the propensity to reach upwards of 150 pounds - and is a species that has seen its record fall numerous times in the last 20-30 years as they seem to just be getting bigger and bigger. Found throughout much of the Eastern/Southeastern United States, the blue catfish has a voracious diet - constantly feeding a seemingly endless appetite for almost anything that moves... shellfish, fish, crabs and crustaceans, insects, even some plant material. Because of the sheer brute size and appetite - blues can impose themselves on other species and, where they are introduced/non-native, they often have a considerable impact on other fish. Still, there is something about the folklore of a giant catfish that draws thousands of anglers to the strongholds of blue catfish across North America for a chance encounter at one of these man sized beasts.
6. Flathead Catfish (Pylodictis olivaris) up to 130+ pounds
Staying close behind its fellow whiskerface is the flathead catfish. Aptly named, the flathead is known for its low, wide profile - where it spends much of its time tucked under logjams, boulders, bridge pilings and other structure - waiting to engulf its unsuspecting prey. The flathead is primarily a predator, aggressively feeding on other fish, crustaceans, worms etc. Particularly large specimens feed almost entirely on other fish. The Flathead is found mainly in large rivers and estuaries - as far West as Arizona, north to Minnesota and on east of Appalachia.
7. Chinook (King) Salmon (Oncorhynchus tshawytscha) - to 125 pounds
The largest of all Pacific salmon species - the Chinook is truly the 'King'. This colossal salmon can exceed 100 pounds. Like some of the other fish found on this list - the Chinook Salmon is born in freshwater, but does migrate out to the ocean for periods of its life, technically making it an anadromous fish. While there are landlocked populations of 'Kings', the true monsters live in natural rivers and oceans... and for the purpose of this list, there are opportunities to take them by rod and reel in clean, fresh water. The Chinook is commonly found in the Pacific coastal rivers of Alaska, Canada, and from Washington state on down to parts of California. The Chinook undergoes tremendous physical changes as adult males reach the spawning phase of their life cycle. As they transition from oceans to freshwater rivers they begin to morph in shape and color from the 'football' shaped silvery fish, to deep reds and purples with exaggerated jaw lines. The King Salmon sustains itself mostly on small crustaceans, shrimp, plankton, crabs and more.
8. Buffalos' (Smallmouth, bigmouth, black) Ictiobus~ to 100lb~
A relatively low radar species in North America, our 3 buffalo species all have the propensity to exceed 70 pounds - and records of triple digit fish being sampled in nets and by other means are out there. Perhaps most commonly found among the uncommon, is the smallmouth buffalo. With a similar profile to a carp (although totally unrelated) this broad shouldered beast is like the fishy version of its furry, horned land mammal counterpart - the buffalo (bison). The smallmouth buffalo, with its small subterminal mouth, is primarily a bottom feeder/grazer that sustains itself on small insects, larvae, and algae. The bigmouth buffalo - similar in appearance but with a more forward facing mouth - feeds more in the pelagic portion of the water column on small plankton, insects, and larvae. The three species of buffalo primarily live in moving waters, rivers and estuaries mostly in the South Central United States up to the US/Canadian border states like Minnesota, North Dakota, and parts of Montana.
9. Striped Bass (Morone saxatilis) - 70-80lb~
Commonly referred to as 'stripers' the striped bass is another coastal species of anadromous fish - born in freshwater but spending much of their lifetime in saltwater. There are still sterile populations of landlocked striped bass in the Eastern United States and areas they have been artificially stocked. In deeper, cooler rivers rich in oxygen and ample food sources such as threadfin shad, large striped bass are happy to set up residency in freshwater river systems for extended periods of time. Large Striped Bass are piscivorous - meaning they eat primarily fish. They are very opportunistic predators that will key in on and feed on a variety of baitfish like bunker and herring... where they launch incredible assaults (or blitzes) on schooling food sources. The striped bass is legendary for its powerful fight by rod and reel.
10. Muskellunge aka 'Muskie' (Esox masquinongy) 60-70 pounds
The largest of the Esox or 'Pike' family, Muskie are one of the most intimidating toothy predators that swim in North American Waters. A solitary hunter, the Muskie is an aggressive ambush predator that spends most of its time in lakes and rivers along grass margins, rocky outcroppings, and any other structure that provides an opportune area to stage an ambush on unsuspecting prey. The Muskie ranges from as far South as the Ozarks and Tennessee up to Northern Canada and Alaska. The species has a long sleek build, growing in excess of 60 inches and over 70 pounds.
Gulf Sturgeon (Acipenser oxyrhynchus desotoi) - over 300lb
Like many sturgeon species - the gulf sturgeon is anadromous and spends much of its time developing its immense size in the ocean. This species is especially shrouded in mystery, and there are very few legitimate claims of specimens caught in freshwater by rod and reel.
*Lake Trout (Salvelinus namaycush) 60lb+~
This prized game and food fish has the propensity to reach over 60 pounds - with specimens over 80 pounds having been sampled on rare occasions, but 40 pound fish are not uncommon. The All Tackle World Record for the species is over 70 pounds. Larger specimens are predatory, feeding primarily on smaller fish. The Lake Trout is primarily found in Northern regions of Canada but exists also in the Great Lakes. The species has been widely introduced to other Northern States of the United States.
Longose Gar (Lepisosteus osseus) upwards of 50 pounds
While this primitive species only reaches about a quarter of the size of its monstrous cousin, the Alligator Gar, the Longnose Gar reaches nearly 6 feet in length and upwards of 50 pounds+. A very well adapted 'survivor' the longnose gar is equipped with armored scales, the ability to breath dissolved oxygen, and can sustain itsself on very little food. An opportunistic feeder, the longnose gar often spends its days lazily cruising t