The Top 11 Longest Fish in the World

Written by AZ Animals Staff
Published: July 12, 2021
Written by AZ Animals Staff
Published: July 12, 2021

Have you ever wondered what are the longest fish in the world? A fish is defined as a member of the phylum Chordata and the subphylum Vertebrata. There are approximately 34,000 species of fish in the world, and scientists are discovering new species every day. While most fish are cold-blooded, there are at least one species of warm-blooded fish. In order to compile this list, we looked only at the total body length of fishes that is alive today. Only verified measurements by a reputable organization were accepted when making this list.

#11. Southern Sunfish – 9 Feet

Biggest Fish: Southern Sunfish
The Southern Sunfish is slightly smaller, measuring about 3 meters (​9.9 feet), and is native to the southwestern Pacific Ocean.

Also called the bump-head sunfish, the largest southern sunfish, according to the Guinness Book of World Records, was 8 feet 11 inches long. This fish caught off Japan’s shores holds the record for the heaviest bony fish at 5,070 pounds. Southern sunfish can be found throughout the Southern Hemisphere, especially around Australia, New Zealand, Chile, and South Africa. The southern sunfish has a unique habit of basking in shallow waters on its side. Scientists believe that this habit encourages seabirds to eat the parasites that often invade their skin so that the animal stays healthier.

#10. Ocean Sunfish – 10 Feet 11 Inches

Biggest Fish: Ocean Sunfish
Ocean sunfish (Mola mola), also known as the common mola. Sunfish don’t have a tail, their dorsal and anal fins are fused together into a rudder-like structure called a clavus. The sunfish swims by flapping its dorsal and anal fins synchronously, like oars.

The largest ocean sunfish reach up to 14 -feet long and are 10-feet wide. These fish live in tropical and temperate waters worldwide, where they feed on small fish, fish larvae, squid, and crustaceans. Ocean sunfish are unique because they have a beak-like structure instead of a mouth. The beak cannot be fully closed. These fish are not good at swimming where they intend to go. The largest on record was caught off Japan’s shores.

#9. Reef Manta Ray – 18 Feet

Biggest Fish: Reef Manta Ray
Reef Manta Rays (Manta alfredi) in a mating formation with several males following a mature female, Komodo National Park, Indonesia.

The largest reef manta ray was 18 feet long, and these fish routinely grow to be 16 feet. They live in the subtropical parts of the Indo-Pacific, but they have been observed at diverse locations in the West Atlantic and Eastern Pacific oceans. These rays have unique cephalic fins at the front of their bodies that they can roll up when they want to swim or unroll to help move water, that contains food, into their mouths.

Learn more about manta rays.

#8. Tiger Shark – 18 Feet

Biggest Fish: Tiger Shark
Tiger Shark interacting with Scuba Diver. Tiger sharks are named for the dark, vertical stripes found mainly on juveniles. As these sharks mature, the lines begin to fade and almost disappear.

A team of researchers recorded a video of an 18-foot tiger shark off the coast of French Polynesia. There have reportedly been even bigger tiger sharks caught, but none have been verified. Tiger sharks are the second most aggressive shark in the ocean. This shark tends to live around the equator, but they have been spotted in waters off Japan and New Zealand. They tend to stay closer to shore during the day and swim out into deeper water at night. Tiger sharks are opportunistic, and they will eat almost anything.

Learn more about Tiger Sharks.

#7. Kaluga – 18.25 Feet

Biggest Fish: Kaluga
Freshwater kaluga ( Huso dauricus ) in the aquarium. The kaluga is a large predatory sturgeon found in the Amur River basin.

The Kaluga is a sturgeon fish that lives most of its life in the Amur River, located between China and Russia. These fish that can grow up to 18.25 feet long are very aggressive. There are unconfirmed reports of them tipping over boats and trying to hurt anglers. They spend part of their lives living near freshwater gravel beds and live part of their lives in saltwater. These fish are unique because they can move part of their mouth to the side of their face to catch fish. Overfishing for their roe has almost caused this fish to go extinct.

#6. Giant Ocean Manta Ray – 20.3 Feet

Biggest Fish: Giant Ocean Manta Ray
Manta rays have two horn-shaped fins protruding from the front of their heads, which has also given them the nickname “devil fish.”

According to researchers at Duke University, the largest giant oceanic manta ray was 20.3-feet long. Generally, the largest ones are near Ecuador, but this manta ray can be found in warm waters throughout the world. Their reproduction rate is much lower than most other fish. Females weigh much more than males. The heaviest giant oceanic manta ray ever recorded weighed over 5,998 pounds. While it has been assumed that manta rays migrated long distances, researchers from the Scripps Institution of Oceanography in San Diego, California, have found that manta rays like to stay at home. Those living off Indonesia’s coast often traveled less than 149 miles annually while those living off Mexico’s coast traveled about 373 miles.

#5. Greenland Shark –23 Feet

Biggest Fish: Greenland Shark
Greenland sharks are native to the North Atlantic waters around Greenland, Canada, and Iceland. They are the only true sub-Arctic shark and the only shark that can tolerate Arctic temperatures year-round.

The Greenland shark can grow up to 23 feet long. It has the longest lifespan of any known living vertebrae. This fish can live to be over 500 years old, and scientists believe that it does not reach sexual maturity until it is 150 years old. This shark has been observed actively hunting seals off Canada, but it generally eats other fish, and it often catches its prey asleep. A large buccal cavity allows it to suck its prey into its mouth, where it often swallows it whole.

Learn more about Greenland Sharks

#4. Great White Shark – 23.3 Feet

Biggest Fish: Great White Shark
Great white shark, Carcharodon carcharias, with a seal. Great whites can reach speeds up to 24 km/hr (15 mph). They use their speed and coloring to help them hunt. They search for prey at the surface of the ocean while swimming below.

Two great white sharks longer than 23.3 feet have been caught, with one being caught in Malta and the other caught near Kangaroo Island in Australia. Typically, great white sharks dine on larger marine animals, and they may only need one large meal a month. These sharks are unique because they capillary network between their swimming muscles. By constantly, swimming they can use this network to raise their body temperatures above the temperature of their environment. These sharks that are spotted globally often migrate. While it is not unusual for great white sharks to migrate shorter distances, like between Mexico and Hawaii, great white sharks in South Africa have migrated over 675 miles to Australia. Scientists still do not understand why they migrate.

Learn more about great white sharks.

#3. Beluga Sturgeon 23.5 Feet

Biggest Fish: Beluga Sturgeon
Underwater portrait of a Beluga, also called European sturgeon (Huso huso). The beluga is the third-largest living species of bony fish in the world.

Beluga sturgeons have been caught that are up to 23.5 feet long. It feeds mainly on other fish, and it is one of the largest predators of the sea. If it cannot get enough fish, then it will eat seal pups and waterfowl. This species lives mainly in the Caspian and Black Seas, but it swims into freshwater to spawn. The female beluga is about 20% larger than the male. Numbers have become greatly reduced through overfishing and poaching because of their roe, which is more often called beluga caviar.

Learn more about Beluga sturgeons.

#2. Basking Shark – 32 Feet

Biggest Fish: Basking Shark
A basking shark, Cetorhinus maximus, swimming off Coll island, Scotland. Due to their passive temperament, basking sharks have the smallest weight to brain weight ratio of any shark.

According to researchers at Duke University, the largest basking fish ever recorded was 32 feet long. While they mainly live in the Atlantic and Pacific Oceans, they have been found in the Mediterranean and the Adriatic Sea, and the Indian Ocean. They live near shorelines where they dine on planktonic crustaceans during the warmer months but migrate further out to sea when temperatures start dropping. Basking sharks are filter feeders who can open their mouths up to 6.5-feet wide.

Learn more about basking sharks.

#1. Whale Shark – 61.7 Feet

Biggest Fish: Whale Shark
Each whale shark has its own unique pattern of spots, much like human fingerprints. A whale shark’s mouth is about 5 feet wide (1.5 m). They have rows of over 300 teeth, but as filter feeders, they do not use these teeth to eat.

According to the Georgia Aquarium, the largest whale shark in the world is 61.7-feet long. These sharks are filter feeders despite having over 300 small teeth inside the bottom and top mouth opening. They live in the Atlantic, Pacific, and Indian Oceans. Even though whale sharks often weigh more than 41,000 pounds, they can only eat zooplankton, such as fish eggs and krill, because they have a very tiny throat opening. The mouth of a whale shark can be up to 4-feet wide. Newborn whale sharks are usually about 23-inches long. In addition to being the biggest fish, they also have one of the longest lifespans because they often live for 130 years.

Learn more about whale sharks.

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