American Oceans

Biggest Jellyfish Ever Recorded

The jellyfish is one of the most fascinating sea creatures the world offers. Nothing is boring about a jellyfish, from its bell-shaped top to the flowing, often venomous tentacles that catch its prey.

biggest jellyfish lion’s mane sea creatures

Looking at the biggest jellyfish ranked, it’s quickly apparent that these creatures can grow to be quite massive. And from the largest jellyfish to the smallest, there are exciting things to learn about them.

Perhaps best known for their stinging properties, jellyfish have stinging cells on their tentacles armed with nematocysts.

Thousands of these can enter the sting when touched by a jellyfish, releasing potent venom. Sometimes the reaction is as simple as a rash; sometimes, it can cause cardiac arrest or death.

biggest lion’s mane jellyfish sting in tentacles

Not all jellyfish are venomous, and not all venomous jellyfish cause severe reactions in humans. Learning more about jellyfish and their many fascinating properties is the best way to understand what makes them so interesting.

Largest Jellyfish Ranked

Here’s a full overview of the largest jellyfish species in the world.

Lion’s Mane Jellyfish

Cyanea capillata, or the Lion’s Mane Jellyfish, is the largest of all the jellyfish species known to man.

biggest lion’s mane jellyfish cyanea capillata

At least that we know of, the biggest one in the world stretches across 120 feet, which is almost as tall as a typical skyscraper building. This jellyfish is sometimes referred to simply as the giant jellyfish.

The Lion’s Mane Jellyfish tend to live in the Northern Hemisphere, where the oceans are colder. It tends to be popular in the Irish Sea, the English Channel, and the North Sea.

Some populations have been found around the Gulf of Mexico, meaning there’s little room for error in determining exactly where they live.

lion’s mane jellyfish on cold north sea

They don’t live much past the first 65 feet of the ocean’s surface, where they reside to feed on small fish and other tiny sea creatures, like zooplankton or smaller jellyfish.

The jellyfish only lives about a year, including its life’s growth and reproductive stages. It cannot breed in waters with low salinity.

Like other jellyfish, the Lion’s Mane Jellyfish has potent neurotoxins in its tentacles, where it uses its stinging cells to catch and immobilize prey.

lion’s mane jellyfish potent neurotoxins in tentacles

Although everyone responds differently to being stung, these neurotoxins are particularly dangerous for humans.

Nomura’s Jellyfish

You’ve heard of people eating jellyfish, right? Well, Nomura’s Jellyfish is one of the edible ones. A Japanese company makes jellyfish ice cream with Normura’s tentacles.

Although it isn’t considered a fine meal, the Nemopilema nomurai is another one of the largest jellyfish species in the world. Nomura’s jellyfish can grow up to 450 pounds in the span of only a year and averages around six feet long.

This feat is accomplished mainly by the hundreds of microscopic mouths it uses to feed on small sea creatures, mostly plankton and larger fish as the jellyfish gets bigger.

They typically live between China and Japan, where they were first discovered in the early 1920s. Nomura’s Jellyfish populations have exploded since their discovery. Fishing in the Yellow Sea and the East China Sea has become increasingly difficult.

Due to their size and massive weight, the explosion of Nomura blooms has become a concern, especially to local fishermen who are tired of pulling giant jellyfish up with their fishing nets. This is especially true considering the toxicity of the creature.

Nomura’s jellyfish are incredibly toxic, especially to humans. And because of their increasing population, stings are increasingly common. A sting from Nomura’s Jellyfish can cause anything from acute pain to death.

Barrel Jellyfish

The largest jellyfish in the United Kingdom has an unfortunate habit of washing up onto shore as it searches for food that hides in shallow waters.

barrel jellyfish in shallow waters of United Kingdom

The Barrel Jellyfish can easily find itself stranded out of the water, forgetting how big it is. Because of its average size of around three feet, the Barrel Jellyfish often acts as a shield for smaller fish.

Some fish and even small crabs know how to maneuver through the tentacles, finding shelter beneath the jellyfish’s bell. 

Otherwise known as Rhizostoma pulmo, the Barrel Jellyfish gets its name from the barrel-like shape of its body.

barrel jellyfish rhizostoma pulmo barrel-like shape body

This jellyfish is most popular in the Adriatic and northeast Atlantic Ocean, Mediterranean Sea, Sea of Azov, and the Black Sea. It’s sometimes found in the southern Atlantic, although not as frequently.

Barrel Jellyfish are not as venomous as other giant jellyfish, which means they do not pose as big of a threat to humans as different types do.

And instead of having thread-like tentacles, Barrel Jellyfish have eight thick tentacles that almost resemble arms. This adds to their barrel-like appearance.

barrel jellyfish with eight thick tentacles

Even though Barrel Jellyfish are not as toxic to humans, one can still cause severe reactions. You might develop a rash, dermatitis, or even ulcers. However, that doesn’t stop people from catching and eating these jellyfish.

Giant Phantom Jellyfish (Stygiomedusa Gigantea)

A giant, ghostly, deep-sea jellyfish from the family Ulmaridae, Stygiomedusa, is sometimes called the giant phantom jelly because sightings are rare. The elusive giant jellyfish has only been seen about once a year for the last 100 years.

Although knowledge of the Stygiomedusa is relatively limited, they are believed to be one of the largest, if not the largest, invertebrate predators of the entire deep-sea ecosystem.

It’s supposed to reach a size of about 33 feet long, with four arm-like tentacles similar to the Barrel Jellyfish.

This massive jellyfish mostly eats small fish and plankton, as far as we know. It has red coloring that helps it camouflage in the dark reaches of the depths of the sea.

And it seems that they lack the typical stinging cells that most jellyfish possess. So their arm-like tentacles help them trap and consume their prey.

Scientists believe the jellyfish resides primarily in the midnight zone of the ocean. The midnight zone refers to some of the ocean’s deepest reaches, extending between 3,200 and 13,000 feet beneath the ocean’s surface.

These jellyfish are believed to exist worldwide, but they have been observed around the Pacific coast of the United States, the Gulf of Mexico, and off the coast of Japan.

Pink Meanie

If the name didn’t make it clear, the Pink Meanie is not the nicest jellyfish out there. It’s prone to consuming other jellyfish.

pink meanie consuming other jellyfish

This slightly cannibalistic jellyfish is a new addition to the jellyfish community. Discovered off the Gulf of Mexico in 2000, they’re also known to exist in some quantity around South Africa.

Some grow as long as 70 feet, though the size can vary. Scientists have used unique genetic techniques to determine that the Pink Meanie is an entirely new species of jellyfish.

They first believed it to be a Drymonema dalmatinum. However, the genetic tests showed this to be incorrect.

pink meanie cannibalistic jellyfish with hundreds of tentacles

An adult Pink Meanie can measure about three feet wide, and it has hundreds of tentacles dangling off its pink bell.

Preying on other, smaller jellyfish, the Pink Meanie can catch multiple tiny jellyfish at one time and trap them in its tentacles.

Although not as deadly as other big jellyfish, the stingers in the tentacles of a Pink Meanie are potent enough for a human to feel.

pink meanie stingers in potent tentacles

And while one might not be so bad, getting stung by hundreds of these cells would be a less than pleasant experience.

Black Sea Nettle

Although they weren’t an official species until 1997, the Black Sea Nettle Jellyfish is a giant jellyfish that resides in the calm, deep waters of the Pacific Ocean.

black sea nettle chrysaora achlyos in pacific ocean

Sometimes known simply as the black jellyfish, the Chrysaora achlyos can grow a three-foot bell and tentacles anywhere from 16 to 20 feet long.

The Black Sea Nettle is primarily known for its unique black pigmentation. They sometimes appear in large numbers, known as a smack of jellyfish.

However, it’s not entirely clear where they spend their time when we can’t see them. Sightings are pretty rare, and usually, you’ll see them in large groups.

rare black sea nettle with stinging tentacles

Black Sea Nettles feed on zooplankton and sometimes other jellyfish. They immobilize their prey with stinging tentacles and drag the creatures to their mouth.

The tentacles surrounding the mouth are typically used most commonly for this task. Nettles can kill small prey with the venom-coated filaments that are ejected from their tentacles.

However, they can only immobilize larger prey and are not deadly to humans. But that doesn’t mean getting stung by one is fun. It still hurts.

black sea nettle venom-coated filaments from tentacles

A fascinating feature of the Black Sea Nettle is that so much about its patterns and behavior is still unknown. However, it is believed that they act as protection for butterfish that hide in the Nettle’s bell when danger seems close.

Tiburonia Granrojo

The fascinating Tiburonia granrojo, sometimes called Big Red, is one of the most extensive and unique in the world.

It lives in the Pacific Ocean, residing in depths of 2,000 to 4,900 feet. They lack tentacles like most jellyfish have, instead of growing between four and seven thick oral arms that are fleshy and somewhat stubby.

“Big Red” is a fitting name, as this jellyfish has a deep red color across its entire form. Its red color and thick arms make it remarkably different from other jellyfish, which caused a lot of confusion when first spotted in the late 1990s.

Big Red has a big, bulky bell to match its fleshy arms. It doesn’t have stinging tentacles like other jellyfish, and it captures its food with the arms instead. For this reason, they are sometimes called “feeding arms.”

As of now, Big Red is the only species of its kind. It’s a member of the family Ulmaridae, and it can grow up to 30 inches. It’s a deep-sea jellyfish, which explains why it’s so much bigger than similar jellyfish.

Australian Box Jellyfish

Not only are Australian Box Jellyfish one of the most significant kinds of jellyfish, but they are among the most popular kinds of jellyfish.

australian box jellyfish in Northern Australia

Almost everyone has heard of a box jellyfish, and most people probably assumed they lived somewhere near Australia.

Sometimes called sea wasps or marine stingers, the Chironex fleckeri reside all across the Indo-Pacific region but mainly off the coast of Northern Australia.

They grow up to 60 tentacles, each as long as ten feet, in four clumps along the base of their eerily transparent bell.

australian box jellyfish chironex fleckeri with 60 tentacles

Box Jellyfish tend to feed on prawns, mangroves, and other small fish. Their venom is used both in the acquisition of food and to defend themselves against predators, like turtles and batfish.

Sea turtles might be immune to jellyfish stings because they are one of the creature’s primary predators.

Unlike other jellyfish, which just float through the water, Box Jellyfish can swim. They can also see, with clusters of eyes on their bells. And their venomous tentacles make them the most venomous marine animal known to the world.

australian box jellyfish long venomous tentacles

Box Jellyfish are deadly to humans. A mysterious increase in unexplained swimming deaths in Australia in the 1940s led researchers to explore and identify the cause as Box Jellyfish.

Atlantic Sea Nettle

The Chrysaora quinquecirrha lives along the Atlantic coast of the United States. It can stretch out to as much as three feet in diameter.

atlantic sea nettle chrysaora quinquecirrha in Atlantic coast

Although smaller than its Pacific counterpart, the Atlantic Sea Nettle is still one of the giant jellyfish in the known world.

The Atlantic Sea Nettle has the typical bell shape known to most jellyfish and is slightly transparent. However, some somewhat pink and yellow hues can be seen in the jellyfish.

Atlantic Sea Nettles are similar to other jellyfish in that they eat small fish, eggs, and whatever other zooplankton they can find. After stinging its prey, it brings it up to its mouth for consumption.

atlantic sea nettle stinging and eat other jellyfish

They can feed almost constantly. They’re also known to eat other jellyfish and occasionally crustaceans.

Atlantic Sea Nettles are mainly prey to sea turtles, similar to other types of jellyfish around the world.

They use their stingers as their primary defensive mechanism, immobilizing some creatures who might be predators.

atlantic sea nettle with toxic venom immobilizing creatures

Atlantic Sea Nettles rarely kill humans, but their venom is toxic to humans and can provoke severe reactions. An allergic reaction could result in death for a human, while the sting itself isn’t considered very harmful.

Wrap Up

Jellyfish can be found all over the world. From the darkest depths of the sea to the shallow waters of the coast, there’s no telling when you might run into one of these giant sea creatures.

And while they might be exciting and beautiful to observe, it’s better for everyone if you watch from a safe distance.

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