When considering day fishing at our favorite fishing holes, generally we catch fish not bigger than 60 to 75 pounds on a rod and reel. Larger fish are always possible using a trotline or net in deeper water or along river channels. Usually, the majority of us catch hand size bluegill bream, slab crappie, largemouth bass, carp, or catfish (best chance to catch a large fish).
In the United States of America, there are some pretty large freshwater fish lurking the deeps of thousands of miles of rivers, deep lakes, ghostly swamps and the endless tributaries that are the life support of healthy rivers. There are bigger and more formidable freshwater fish prowling the freshwater basins in the more remote parts of the world. Monstrous fish, so huge that some of them are as big as the cars that we drive and others so aggressive that they could possibility swallow a man whole, if they were hungry enough.
Let's take a look together at the Monster Leviathans: “The Planet's Largest Freshwater Fish That You Probably Didn't Know About” and thank our lucky stars that we haven't come face-to-face with one of these monsters at our favorite fishing or swimming hole.
Arapaima

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The Arapaima (as known as the “Paiche”) is one of the largest freshwater fish in the world reaching lengths up to 14 ¾ feet and weighing as much as 440 lbs. A native fish to the Amazon, these fish are commonly raised in commercial farm ponds, because of its delicious meat and protein many poor rural regions of the Amazon can easily obtain.
Mekong Giant Catfish

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The Mekong Giant Catfish is considered the most endangered fish in Southeast Asia and in a last ditch attempt to save the fish from complete extinction, the World Conservation Union has classified the Mekong Giant Catfish as critically endangered making it a crime to harvest. The Mekong Giant Catfish can grow to more than 660 pounds in the Cambodian Mekong River Basin and grow to lengths as big as a Volkswagen.
Giant White Sturgeon

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The Giant White Sturgeon is a freshwater prehistoric looking fish with sweet meat that is considered to be a delicacy in many parts of the world. Found mainly in the Yangtze River in China, the Giant While Sturgeon can reach lengths of exceeding 12 feet and weigh more than 950 pounds. There have been some documented cases in which Giant White Sturgeons have been caught by sports fishermen weighing in at more than 1,100 pounds and nearing 16 feet in length.
Chinese Paddlefish

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The Chinese Paddlefish are considered one of the planet's largest freshwater fish, which are found in the Yangtze River in China. These fish are quickly disappearing and quiet frankly, the scientists are scratching their heads as to the reason why, but commercial fishing and pollution are two possible reasons as to why. The Chinese Paddlefish can grow to more than 1000 lbs and reach lengths of 23-feet or greater. Everything is bigger in China.
Giant Stingray

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The Giant Stingray found mostly in the river basins of Cambodia and China, but are found in other freshwaters throughout Asia, can grow up to 5 meters (16.4 feet) in length and weigh as much as 1,100 lbs. Just like with other stingray species, the Giant Stingray has a sharp, deadly spear-like barb at the tip of its tail that can be used to defend itself with a potentially deadly outcome.
Bull Shark

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The Bull Shark is considered to be one of the most dangerous sharks in the world, because it can survive both in the salt waters of the oceans and the brackish and freshwaters of inland rivers and tributaries. The Bull Shark can grow to 500 lbs and reach lengths of nearly 12 feet. They have been known to attack and kill humans. This type of shark is found in the Ganges River basin of India, the Mississippi River Basin in North America, the Amazon River in Peru, and in Lake Nicaragua in Central America.
Northern River Shark (Glyphis sp. C.)

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The Northern River Shark is only known to inhabit the Adelaide and Alligator River systems in the Northern Territory of Australia, but the numbers are apparently on the decline due to heavy fishing and environmental toxins. The Northern River Shark can reach 2 to 3 meters in length and have rows razor-sharp teeth, just like its saltwater cousins.
Alligator Gar

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The Alligator Gar can reach weights up to 300 pounds and are commonly found long the Mississippi River basin of North America, but can be found in lakes and other rivers that connect with the Mississippi River. The larger fish can grow to lengths greater than six-foot and there have been reported attacks on humans, but most are believed to have been accidental attacks as the fish probably mistaken hands and feet as food. Alligator Gar have razor-sharp needle-like teeth filling the short snout and armor-like scales covering its body.
Blue Catfish

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The Blue Catfish is closely related to the channel catfish and are found in rivers and reservoirs throughout North America, northern Guatemala east of the Appalachians. These fish have been documented to grow up to 150 pounds, but some legends exist that the Blue Catfish can reach weighs up to 350 pounds, but there hasn't ever been a Blue Catfish scientifically documented in that size category.
Giant Carp

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The Giant Carp often harvested for its meat, which is considered to be a delicacy throughout Asia can reach weighs up to 660 pounds and easily achieve lengths of 6 ½ feet.
Cool article. I used to go fishing with my father and brother and would run amile if anything longer than the length of my forearm was pulled out of the water. What I would do with the sight of these babies coming at me I have no idea! Very informative! Cheers!