The “biggest fish ever caught” is complex, with various interpretations. The answer depends significantly on the specific criteria applied. Different definitions consider the largest known species, the heaviest or longest individual recorded, or the largest fish caught through sport fishing methods. Understanding these distinctions clarifies what truly constitutes the biggest fish based on differing perspectives.
The Ocean’s Giants: Overall Largest Fish
The undisputed title for the overall largest fish species belongs to the whale shark, Rhincodon typus. These colossal creatures are the largest fish in the ocean, reaching lengths up to 18.8 meters (60 feet) and weighing over 21.5 tonnes (40 tons). Whale sharks are gentle filter feeders, consuming plankton and small organisms as they navigate warm tropical waters.
Following the whale shark, the basking shark, Cetorhinus maximus, is the second-largest fish species. These migratory sharks attain lengths of about 12.2 meters (40 feet) and weigh approximately 16 tonnes (19 tons). Like whale sharks, basking sharks are filter feeders, utilizing their wide mouths to strain plankton from the water near the surface.
Giants of the Deep: Largest Bony Fish
The largest bony fish in the ocean present impressive dimensions. The ocean sunfish, Mola mola, is the heaviest bony fish, with adults weighing around 2.3 tonnes. These fish grow up to 3.3 meters (10.8 feet) in length and are found in tropical and temperate oceans. Their distinctive flat, disc-like shape contributes to their considerable mass.
The oarfish, Regalecus glesne, is known for its extraordinary length. This species is the longest extant bony fish, with individuals ranging from 7 to 8 meters (23 to 26 feet) in total length. Some reports suggest they can reach up to 11 meters (36 feet), though their slender bodies mean they are not as heavy as the ocean sunfish, weighing up to 272 kg (600 lb).
Freshwater Behemoths: Largest Freshwater Fish
Freshwater environments host their own giants. The beluga sturgeon, Huso huso, is the largest freshwater fish, growing up to 7.3 meters (23.6 feet) long and weighing as much as 1,570 kg (3,463 pounds). This species is found primarily in the Caspian and Black Seas, and also inhabits associated freshwater lakes and rivers. Its population has faced severe overfishing due to the high demand for its roe, known as caviar.
The Mekong Giant Catfish, Pangasianodon gigas, has individuals recorded at over 300 kilograms (646 pounds) and exceeding 3 meters (9 feet) in length. This species is native to the Mekong River basin in Southeast Asia. The alligator gar, Atractosteus spatula, is the largest entirely freshwater fish in North America, with a verified specimen weighing 148.5 kg (327 lb) and measuring 2.6 meters (8.5 ft).
Record-Breaking Catches: The Biggest Ever Caught by Anglers
When considering the “biggest fish ever caught” by an angler, the focus shifts to individual catches documented by the International Game Fish Association (IGFA). The largest fish caught on rod and reel and certified by the IGFA is a great white shark, weighing 2,664 pounds (1,208 kg). This catch was made off Ceduna, Australia, in 1959 by angler Alfred Dean. Due to protection efforts for great white sharks, this record is unlikely to be surpassed.
Other significant angling records include a tiger shark weighing 1,785 pounds 11 ounces (810 kg), caught in Australian waters in 2004. The fourth heaviest fish recorded by the IGFA is a black marlin, weighing 1,560 pounds (707.6 kg), caught in Peru in 1953. For freshwater, the largest catfish caught on rod-and-reel and certified by the IGFA was a 297-pound 9-ounce Wels catfish, reeled in from Italy’s River Po in 2010.