What Is The Biggest Fish In The World?

By Deb Goncalves on September 1 2020 in Environment

A whale shark, the world's largest fish. Image credit: Andrea Izzotti/Shutterstock.com
A whale shark, the world's largest fish. Image credit: Andrea Izzotti/Shutterstock.com
  • The biggest fish in the world is the whale shark. It is a shark not a whale.
  • Many believe blue whales to be the largest fish, but they are considered to be mammals not fishes.
  • The largest bony fish is the oddly shaped ocean sunfish. Its nickname is the "swimming head."

Although many people credit the blue whale as the biggest fish in the world, it is the whale shark which actually qualifies for the title. Although the blue whale is undoubtedly the largest living animal on our planet, it is a mammal and not a fish. Instead, the whale shark, a true fish belonging to the Chondrichthyes class, holds the record. The second and third biggest fishes in the world are the basking shark and the great white shark, respectively. While all these three species are cartilaginous fishes, the largest bony fish is the ocean sunfish, and it comes in at number six on our list of the world's biggest fish. 

The Largest Fish: Whale Shark

Image credit: Krzysztof Odziomek/Shutterstock.com

The whale shark or Rhincodon typus, the world's largest fish, is found in the warm tropical oceans where it feeds on smaller fish and plankton. These fishes have lifespans ranging from 80 to 130 years.

How Big Is The Whale Shark?

According to National Ocean Services, whale sharks can grow up to 40 feet and weigh as much as 40 tons. However, it is rare to find a whale shark that is close to 40 feet long. The Encyclopedia of Life has reported that whale sharks are generally between 18 to 33 feet long. 

Biggest Whale Shark On Record

There is a lot of uncertainty as to the size of the largest specimen of whale shark ever caught due to the variety of methods used to measure the caught specimens. In 1868, an Irish scientist E.P. Wright claimed to have observed whale sharks that were over 50 ft long. In 1934, a whale shark that rammed onto a ship in the south Pacific Ocean was estimated to be about 55 ft long. Satellite tracking of whale sharks have reported two specimens to be anywhere between 49 ft and 59 ft long.

Coming In Second: Basking Shark

Image credit: Martin Prochazkacz/Shutterstock.com

The Cetorhinus maximus is commonly known as the basking shark. It comes in on our list at number two. It can be found around the world, as it swims in arctic and temperate waters. Its lifespan is up to 50 years, and it enjoys feasting on zooplankton.

How Big Is The Basking Shark?

A basking shark typically weighs 5.5 tons, and it is usually over 32 feet long. According to Britannica, the basking shark can grow to be as long as 46 feet. 

Biggest Basking Shark On Record

The biggest basking shark recorded was caught in a herring net in 1851. It was said to have been 40 feet long. The fish was found in the Bay of Fundy, a bay located between New Brunswick and Nova Scotia, Canada. 

Third Biggest Fish: Great White Shark

Image credit: Marc Henauer/Shutterstock.com

The Carcharodon carcharias is the most famous shark due to its attacks on humans. The great white shark can be found all around the world. Popular locations include South Africa, Australia, New Zealand, Mexico, Guadalupe Island, California, and the North Atlantic region. It feeds on anything from small fish to large mammals. This shark lives up to 70 years, according to a 2014 study

How Big Is The Great White Shark?

The third-largest fish on our list is generally 15 to 20 feet long. It weighs 2.5 tons (4,000-7,000 pounds) and sometimes more.

Biggest Great White Shark On Record

In January 2019, the Independent reported divers spotting the biggest great white shark near Oahu, Hawaii. It was nearly 23 feet long, weighed 5,000 pounds, and was believed to be 50-years-old.

The Biggest Bony Fish: Ocean Sunfish

A bump headed sunfish. Image credit: Hasama Underwater Park/Wikimedia.org

The ocean sunfish, Mola mola, is the biggest bony fish in the world; overall, it is number six on our list of biggest fishes. The ocean sunfish lives up to ten years, and some believe even longer than that; though, researchers are still unsure. It lives in tropical waters, and its preferred meal is the jellyfish.

How Big Is The Ocean Sunfish?

The ocean sunfish grows up to ten feet long, and it can weigh up to 2.5 tons. They are considered to be the heaviest bony fish. The most interesting aspect of this fish is that it looks like half of a fish. This is because the ocean sunfish's back fin never grows. As it gets older, the tail folds into itself.

Biggest Ocean Sunfish On Record

The biggest ocean sunfish was caught off the coast of Japan in 1996. This fish was 5,070 pounds and classified as a Mola mola, one of the six species of the ocean sunfish. However, National Geographic reported that in 2003 scientists realized that the fish was actually a Mola alexandrini ocean sunfish. The Mola alexandrini has a “prominent head shape, lending it the common name the ‘bump-headed sunfish,’” according to Live Science.

What Is The Biggest Fish In The World?

RankAnimalScientific nameTaxonomic ClassKnown maximum mass [tonnes]
1Whale sharkRhincodon typusChondrichthyes (Cartilaginous Fish)21.5
2Basking sharkCetorhinus maximusChondrichthyes (Cartilaginous Fish)19
3Great white sharkCarcharodon carchariasChondrichthyes (Cartilaginous Fish)3.324
4Tiger sharkGaleocerdo cuvierChondrichthyes (Cartilaginous Fish)3.110
5Giant oceanic manta rayManta birostrisChondrichthyes (Cartilaginous Fish)3.000
6Ocean sunfishMola molaOsteichthyes (Bony Fish)2.300
7Southern sunfishMola alexandriniOsteichthyes (Bony Fish)2.300
8Beluga sturgeonHuso husoOsteichthyes (Bony Fish)2.072
9Sharptail molaMasturus lanceolatusOsteichthyes (Bony Fish)2.000
10Hoodwinker sunfishMola tectaOsteichthyes (Bony Fish)1.870
11Reef manta rayManta alfrediChondrichthyes (Cartilaginous Fish)1.400
12Greenland sharkSomniosus microcephalusChondrichthyes (Cartilaginous Fish)1.397
13Megamouth sharkMegachasma pelagiosChondrichthyes (Cartilaginous Fish)1.215
14KalugaHuso dauricusOsteichthyes (Bony Fish)1.140
15Giant devil rayMobula mobularChondrichthyes (Cartilaginous Fish)1.000

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