Top 10 Largest Bony Fish by Maximum Weight in the World
The ten heaviest bony fish species in the world, ranked by maximum recorded body weight — from the giant sunfish and ocean sunfish to the beluga sturgeon and Atlantic bluefin tuna.
Bony fish (Osteichthyes) make up the vast majority of the world's fish species, but the true giants of the fish world are cartilaginous — sharks and rays. Among bony fish, the heaviest species are dominated by the odd-looking sunfish (family Molidae), which can weigh over two tonnes, and the massive sturgeon that ply the rivers of Eurasia. Tuna, groupers, and halibut round out the list.
This list ranks the ten heaviest bony fish species by maximum recorded body weight, based on verified scientific records from FishBase, the IUCN, and peer-reviewed ichthyology literature. Cartilaginous fish (sharks, rays, and chimaeras) are excluded. Maximum weight means the heaviest confirmed individual specimen ever recorded for the species.
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Maximum weight (kg)
Maximum weight (kg)
Giant Sunfish (Mola alexandrini)
2744 kg
Ocean Sunfish (Mola mola)
2300 kg
Beluga Sturgeon (Huso huso)
2072 kg
Sharptail Mola (Masturus lanceolatus)
2000 kg
Hoodwinker Sunfish (Mola tecta)
1870 kg
Atlantic Bluefin Tuna (Thunnus thynnus)
684 kg
Giant Grouper (Epinephelus lanceolatus)
400 kg
Mekong Giant Catfish (Pangasianodon gigas)
350 kg
Atlantic Halibut (Hippoglossus hippoglossus)
320 kg
Chinese Sturgeon (Acipenser sinensis)
250 kg
The ranking
1
Giant Sunfish (Mola alexandrini)
The giant sunfish, also known as the bumphead sunfish or Ramsay's sunfish, is the heaviest bony fish in the world. The largest confirmed specimen weighed 2,744 kg (6,050 lb) and was caught off Japan in 1996. Unlike most fish, the giant sunfish has no true tail fin — its body ends in a rounded clavus. It is found in temperate and tropical oceans worldwide and feeds primarily on jellyfish.
Scientific name: Mola alexandriniFamily: MolidaeMax length: 3.3 mRange: Temperate and tropical oceansStatus: Least Concern
2
Ocean Sunfish (Mola mola)
The ocean sunfish, or common mola, is the second-heaviest bony fish with a maximum recorded weight of 2,300 kg (5,100 lb). It is the most widely distributed of the sunfish species and is a common sight basking at the ocean surface, where it warms itself after deep dives. The ocean sunfish can produce up to 300 million eggs at once — more than any other vertebrate — and its diet consists mainly of jellyfish, salps, and small fish.
Scientific name: Mola molaFamily: MolidaeMax length: 3.1 mRange: Global (tropical and temperate seas)Status: Vulnerable
3
Beluga Sturgeon (Huso huso)
The beluga sturgeon is the largest freshwater fish in the world and the heaviest anadromous fish, with a confirmed maximum weight of 2,072 kg (4,570 lb). Native to the Caspian and Black Sea basins, the beluga is the source of the world's most expensive caviar — beluga caviar can sell for over $10,000 per kilogram. Overfishing and habitat loss have made the beluga sturgeon critically endangered, with wild populations declining by over 90% in the last century.
Scientific name: Huso husoFamily: AcipenseridaeMax length: 7.2 mRange: Caspian and Black Sea basinsStatus: Critically Endangered
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4
Sharptail Mola (Masturus lanceolatus)
The sharptail mola, also known as the sharp-tailed sunfish, reaches a maximum weight of approximately 2,000 kg (4,400 lb). Unlike other sunfish, the sharptail mola has a pointed clavus (pseudo-tail) rather than the rounded one seen in Mola species. It is found in tropical and subtropical waters worldwide and is the least studied of the large sunfish species, with much of its biology remaining unknown.
Scientific name: Masturus lanceolatusFamily: MolidaeMax length: 3.0 mRange: Tropical and subtropical oceansStatus: Least Concern
5
Hoodwinker Sunfish (Mola tecta)
The hoodwinker sunfish is the most recently described large sunfish species, formally identified in 2017. It reaches a maximum weight of approximately 1,870 kg (4,100 lb). The species was named 'hoodwinker' because it had been hiding in plain sight — misidentified as the common ocean sunfish for decades. It is found in the temperate waters of the Southern Hemisphere, including New Zealand, Australia, South Africa, and Chile.
The Atlantic bluefin tuna is the largest tuna species and one of the largest bony fish, with a maximum recorded weight of 684 kg (1,508 lb). The largest confirmed specimen was caught off Nova Scotia, Canada. Atlantic bluefin are warm-blooded, capable of maintaining body temperatures above the surrounding water, which allows them to hunt in cold waters. They are highly migratory and can cross the Atlantic Ocean in as little as 60 days.
Scientific name: Thunnus thynnusFamily: ScombridaeMax length: 4.6 mRange: North Atlantic OceanStatus: Near Threatened
7
Giant Grouper (Epinephelus lanceolatus)
The giant grouper, also known as the brindle bass or Queensland grouper, is the largest grouper species in the world, reaching a maximum weight of 400 kg (880 lb). Found across the Indo-Pacific from the Red Sea to Hawaii, this solitary reef dweller can live for over 40 years. Giant groupers are apex predators on coral reefs, feeding on crustaceans, rays, and small sharks. They are listed as Vulnerable due to overfishing in parts of their range.
The Mekong giant catfish is the largest freshwater fish in Southeast Asia, with a maximum recorded weight of 350 kg (770 lb). Endemic to the Mekong River system, the species is critically endangered due to overfishing, dam construction, and habitat degradation. In Thai and Lao culture, the Mekong giant catfish is considered a sacred species, and conservation efforts include captive breeding programs and fishing bans during spawning season.
The Atlantic halibut is the largest flatfish species in the world, with a maximum recorded weight of 320 kg (710 lb). Found in the cold waters of the North Atlantic, this bottom-dwelling predator can live for over 50 years. Atlantic halibut have both eyes on the right side of their body and lie flat on the sea floor, camouflaging themselves to ambush prey. They are an important commercial fish, though wild populations have been heavily overfished.
Scientific name: Hippoglossus hippoglossusFamily: PleuronectidaeMax length: 4.7 mRange: North Atlantic OceanStatus: Near Threatened
10
Chinese Sturgeon (Acipenser sinensis)
The Chinese sturgeon is a large anadromous fish native to the Yangtze River and the East and Yellow Seas of China, reaching a maximum recorded weight of 250 kg (550 lb). The species is critically endangered, with its population declining by over 97% in the last 50 years, primarily due to the construction of the Three Gorges Dam and other dams along the Yangtze that block its spawning migration routes. Captive breeding programs have had limited success in maintaining wild populations.
Scientific name: Acipenser sinensisFamily: AcipenseridaeMax length: 5.0 mRange: Yangtze River, East and Yellow SeasStatus: Critically Endangered
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Full comparison
#
Name
Scientific name
Family
Max length
Range
Status
1
Giant Sunfish (Mola alexandrini)
Mola alexandrini
Molidae
3.3 m
Temperate and tropical oceans
Least Concern
2
Ocean Sunfish (Mola mola)
Mola mola
Molidae
3.1 m
Global (tropical and temperate seas)
Vulnerable
3
Beluga Sturgeon (Huso huso)
Huso huso
Acipenseridae
7.2 m
Caspian and Black Sea basins
Critically Endangered
4
Sharptail Mola (Masturus lanceolatus)
Masturus lanceolatus
Molidae
3.0 m
Tropical and subtropical oceans
Least Concern
5
Hoodwinker Sunfish (Mola tecta)
Mola tecta
Molidae
2.4 m
Southern Hemisphere temperate waters
Least Concern
6
Atlantic Bluefin Tuna (Thunnus thynnus)
Thunnus thynnus
Scombridae
4.6 m
North Atlantic Ocean
Near Threatened
7
Giant Grouper (Epinephelus lanceolatus)
Epinephelus lanceolatus
Serranidae
2.7 m
Indo-Pacific (Red Sea to Hawaii)
Vulnerable
8
Mekong Giant Catfish (Pangasianodon gigas)
Pangasianodon gigas
Pangasiidae
3.0 m
Mekong River basin, Southeast Asia
Critically Endangered
9
Atlantic Halibut (Hippoglossus hippoglossus)
Hippoglossus hippoglossus
Pleuronectidae
4.7 m
North Atlantic Ocean
Near Threatened
10
Chinese Sturgeon (Acipenser sinensis)
Acipenser sinensis
Acipenseridae
5.0 m
Yangtze River, East and Yellow Seas
Critically Endangered
How we ranked this
Species are ranked by the maximum confirmed body weight in kilograms (kg) as recorded in peer-reviewed scientific literature, FishBase, and the IUCN Red List assessments. Only verified weights from captured or scientifically documented specimens are included. Species for which the maximum weight is uncertain or derived from anecdotal reports are excluded. All species listed belong to the class Osteichthyes (bony fish). Rank 1 is the heaviest species.
FAQ
What is the heaviest bony fish in the world?
The heaviest bony fish is the giant sunfish (Mola alexandrini), with a confirmed maximum weight of 2,744 kg (6,050 lb). For many years, the ocean sunfish (Mola mola) was believed to be the heaviest, but the giant sunfish was reclassified as a separate species in 2017, and it holds the record.
What is the difference between bony fish and cartilaginous fish?
Bony fish (Osteichthyes) have skeletons made of bone, while cartilaginous fish (Chondrichthyes) — sharks, rays, and chimaeras — have skeletons made of cartilage. The largest fish overall are cartilaginous: the whale shark can reach 21.5 tonnes, far exceeding any bony fish. There are approximately 30,000 species of bony fish compared to about 1,200 species of cartilaginous fish.
Why are sunfish so flat and why do they have no tail?
Sunfish of the family Molidae have a unique body shape that evolved from their tetraodontiform ancestors (pufferfish and boxfish). They lack a true tail fin — instead, they have a 'clavus,' a rounded or pointed structure formed from modified dorsal and anal fin rays. Their flattened body shape allows them to dive deep and then spend long periods basking at the surface to warm up after cold dives.