Biggest Fish in the World: The 10 Largest Fish by Weight

This ranking uses the maximum mass given in Wikipedia's List of largest fish. Tonnes are metric (1,000 kg).

• 1st, whale shark: 21.5 tonnes
• 2nd, basking shark: 16 tonnes, up to 14 m (46 ft)
• 3rd, great white shark: 3.324 tonnes, up to 7 m (23 ft)
• 4th, tiger shark: 3.11 tonnes (unconfirmed)
• 5th, giant oceanic manta ray: 3 tonnes, up to 5 m (16 ft)
• 6th, giant sunfish (Mola alexandrini): 2.744 tonnes
• 7th, ocean sunfish (Mola mola): 2.3 tonnes
• 8th, beluga sturgeon: 2.072 tonnes
• 9th, sharptail mola: 2 tonnes
• 10th, hoodwinker sunfish: 1.87 tonnes

Five of the ten are sharks or rays, and four are sunfishes. The sunfishes are the heaviest bony fish; see our ocean sunfish page for how to tell a mola apart.

NOAA's National Ocean Service calls the whale shark the biggest fish in the ocean. It can grow to about 40 feet, and by some estimates weigh as much as 40 tons; longer fish are uncommon. Wikipedia's list gives average lengths of 9 to 14.5 m (30 to 48 ft) and says the largest verified, reliably measured individual was a female from the Arabian Sea with a standard length of 15 m and an estimated total length of 18.8 m (62 ft).

The biggest fish eats some of the smallest food. NOAA says whale sharks strain plankton, schooling fish and squid from the water through mouths about a metre wide. They live in all tropical and warm-temperate seas, in water of about 68 to 77°F, and scientists estimate a lifespan of roughly 60 to 100 years, though exact longevity is unknown.

The answer depends on what you count:

• Including rays: the giant oceanic manta ray, 3 tonnes and 5 m (16 ft) (Wikipedia). Rays are cartilaginous fish like sharks, so some lists exclude them.
• Heaviest bony fish: the giant sunfish, Mola alexandrini, at 2.744 tonnes, with a length of 3.3 m (11 ft). The ocean sunfish, Mola mola, reaches 2.3 tonnes (Wikipedia).
• Longest bony fish: the giant oarfish. Wikipedia reports one of 13.7 m (45 ft) struck by a steamship, mature fish usually over 6 m (20 ft), and a recorded specimen of 7.6 m (25 ft) weighing 275 kg (606 lb).
• Tuna and marlin: Atlantic bluefin tuna (verified 679 kg, 4.4 m) and black marlin (verified 708 kg), with reported fish of 910 kg and 750 kg respectively (Wikipedia).

The whale is bigger, and it is not a fish. NOAA Fisheries gives the blue whale up to 110 feet long and 330,000 pounds, calls it the largest animal ever to have lived, and classes it as a mammal, one of the baleen whales. The whale shark, at up to about 40 feet (NOAA), is a true fish, a shark.

Wikipedia's list gives the giant freshwater stingray, Himantura polylepis, as the heaviest verified freshwater fish: the largest verified specimen weighed 300 kg (660 lb) and measured 4 m (13 ft), with unverified reports of 600 kg and 5 m. Other freshwater giants include the arapaima, which the Smithsonian's National Zoo gives at up to 440 pounds, and the beluga sturgeon from the top 10 above.

Two extinct fish top every list. Megalodon (Otodus megalodon) is estimated at 17 to 24.3 m (56 to 80 ft), and a 24.3 m animal is estimated at about 94 tonnes (Wikipedia). Leedsichthys, a Jurassic filter-feeding bony fish, is the largest bony fish known. Older estimates of 21 to 27 m (69 to 89 ft) are what circulate on social media, but Wikipedia reports a 2013 estimate of a maximum 16.5 m (54 ft) and 49 tonnes. Bigger numbers for extinct fish usually come from older estimates made from incomplete fossils.

Probably none. The sailfish is the fish usually quoted, but Wikipedia reports that the old estimate of 35 m/s (about 80 mph) is contradicted by newer studies, which find sailfish do not exceed 10 to 15 m/s (about 20 to 35 mph). Measured during real hunts, their bursts reached about 7 m/s (15 mph) and did not pass 10 m/s. For comparison, Wikipedia gives the barracuda bursts of up to 27 mph.

The same fish can appear with very different sizes, and it is usually for one of these reasons:

• Verified versus reported: Wikipedia marks the Greenland shark at 7.3 m reported but 6.4 m verified, and the black marlin at 708 kg verified but up to 1,360 kg in exceptional estimates.
• Standard versus total length: the record whale shark was 15 m standard length (snout to base of tail) and an estimated 18.8 m total length.
• Tons versus tonnes: NOAA uses US tons; Wikipedia uses metric tonnes.
• Verified record versus ranking figure: Wikipedia's largest reliably documented beluga sturgeon, caught in the Volga estuary in 1827, weighed 1,474 kg (3,250 lb) and measured 7.3 m (24 ft); the 2.072-tonne figure used in the top-10 ranking above is a separate, undated maximum.

When you compare numbers, compare the same kind of measurement.

Research and drafting for this page were assisted by AI and checked line by line against the sources listed below. Every number names the organisation it comes from, and where sources disagree we say so instead of picking one silently. Prices and rules are given with the date we checked them; they change, so confirm before you rely on them. If you find an error, tell us and we will correct it.

All of the heaviest living fish are ocean fish. By the maximum weights in Wikipedia's List of largest fish, the top three are:

• Whale shark: 21.5 tonnes; NOAA's National Ocean Service calls it the biggest fish in the ocean, at up to about 40 feet.
• Basking shark: 16 tonnes. Wikipedia says adults are typically 7.9 m (26 ft), some reach 9 to 11 m, and the largest recorded was 12.27 m (40.3 ft).
• Great white shark: 3.324 tonnes, up to 7 m (23 ft).

Both giants are filter feeders. Wikipedia notes one difference in how they feed: the whale shark can actively pump water over its gills, while the basking shark relies only on the water it pushes through by swimming, filtering up to 500 short tons an hour at 5 m long.

These are the two fish most often reported as 'the biggest fish' in sightings, and they are easy to tell apart once you know what to look for (Wikipedia):

• Pattern: the whale shark is dark grey with pale grey or white spots and stripes, unique to each fish; the basking shark is plain dark brown to black or blue above, fading to dull white below.
• Head and mouth: the whale shark has a wide mouth at the very front of a flat head; the basking shark has a conical snout.
• Gills: the basking shark's gill slits are so long they almost ring the head, top and bottom.
• Body: the whale shark has three prominent ridges along each side.
• Where: whale sharks live in tropical and warm-temperate seas (NOAA); basking sharks are found in temperate oceans and are often seen feeding at the surface (Wikipedia).

The whale shark is listed as Endangered by the IUCN, after a decline of more than 50% over 75 years; the global population is estimated at about 130,000 to 200,000 (Wikipedia). Watch from a distance and follow local rules for approaching it.

The largest fish ever landed on rod and reel is a great white shark caught by Alf Dean off southern Australia in 1959, weighing 1,208 kg (2,663 lb), the largest white shark recognised by the International Game Fish Association (Wikipedia's Great white shark size article). It is unlikely to be beaten: One Outdoors' guide to IGFA records notes that great whites and other sharks are no longer eligible for new records under the IGFA's protected-species policy.

The heaviest non-shark all-tackle records listed in One Outdoors' guide to IGFA records:

• Black marlin: 1,560 lb, Cabo Blanco, Peru, 1953
• Atlantic bluefin tuna: 1,496 lb, Aulds Cove, Nova Scotia, 1979
• Atlantic blue marlin: 1,402 lb 2 oz, Vitória, Brazil, 1992
• Pacific blue marlin: 1,376 lb, Kona, Hawaii, 1982
• Swordfish: 1,182 lb, Iquique, Chile, 1953

These are rod-and-reel records, so they are far below the sizes the same species reach in the wild; compare the maximum weights earlier on this page.