The World’s 9 Largest Jellyfish

Jellyfish are incredibly unique creatures that have been the focus of scientific curiosity for hundreds of years. Based on recent discoveries in the fossil record, it has been determined that jellyfish have existed on Earth as far back as 500 million years. Today, there are over 2,000 recognized species of jellyfish that inhabit every ocean of the world; however, scientists speculate that there are thousands of species yet to be discovered. 

Jellyfish are well known for their bright colors, long tentacles, and sometimes painful stings. They come in a diverse range of colors including blue, pink, purple, yellow, and orange. Many are translucent and some, like the crystal jellyfish, have a unique trait called bioluminescence, allowing them to glow in the dark. Although jellyfish are beautiful, many can be venomous and some are lethal. This article explores a few of these amazing creatures. Here are the world’s largest jellyfish based on maximum bell diameter, which is the “head” of the jellyfish. 

#9 Atlantic Sea Nettle – 10 Inches

The Atlantic sea nettle jellyfish, Chrysaora quinquecirrha, can have a bell diameter of up to 10 inches and tentacles that can reach over 1.5 feet long. This jellyfish is found on the Atlantic coast of the U.S., where it is preyed upon by sea turtles, ocean sunfish, and larger jellyfish.

The Atlantic sea nettle also has an interesting symbiotic relationship with blue crabs. The jellyfish provides the blue crab with food and shelter, and the blue crab removes parasites and debris from the jellyfish. The sting from an Atlantic sea nettle can cause moderate discomfort, but it is not lethal to humans.

#8 Australian Box Jellyfish – 19 Inches

The largest recorded bell size of an Australian box jellyfish, Chironex fleckeri, is 19 inches in diameter. However, on average, their bells are 6-9 inches with tentacles up to 10 feet long. The Australian box jellyfish is nicknamed “sea wasp” because of its barbed tentacles, which are incredibly venomous.

It is regarded as one of the deadliest creatures on the planet. One sting can cause paralysis, cardiac arrest, and death in under three minutes. Box jellies are said to be responsible for at least 70 deaths in Australia since 1954. In 2010, a 10-year-old Australian girl was stung by a box jellyfish, and her recovery was considered nothing short of a miracle.

#7 Pink Meanie – 2.5 to 3 Feet

The largest confirmed pink meanie jellyfish, Drymonema larson, was sighted in the Gulf of Mexico and had a bell diameter of about three feet. Some unconfirmed anecdotal accounts have reported diameters up to five feet. These jellyfish can have stinging tentacles as long as 70 feet and have been documented entangling and consuming over 30 smaller moon jellyfish at a time.

Due to the rarity of the pink meanie jellyfish, it was not officially classified as a new species until 2014. The pink meanie was also found to represent a new genus of jellyfish. This jellyfish can cause a painful sting, but it is not lethal.

#6 Giant Phantom Jellyfish – 3.3 Feet

The giant phantom jellyfish, Stygiomedusa gigantea, is a deep-sea jellyfish that can have a bell diameter of 3.3 feet. This jellyfish has four curtain-like oral arms that can reach over 33 feet long. Researchers believe it uses those long, flowing arms to capture prey. Smaller creatures also hide in the folds of these arms to avoid predators in the deep ocean.

This jellyfish can be found in depths of up to 22,000 feet in oceans around the world, with the exception of the Arctic. Depths from around 3,280 to 9,842 feet are called the midnight zone because no sunlight reaches it. The first giant phantom jellyfish was seen in 1899 and has only been seen around 100 times in 125 years.

#5 Barrel Jellyfish – 3.3 Feet

Barrel jellyfish, Rhizostoma pulmo, can grow to around 3.3 feet in diameter. They are commonly found in the northeast Atlantic, especially off the coasts of Britain. They can also be found in the Mediterranean, Adriatic, and Black seas. Barrel jellyfish mainly eat plankton found in shallow waters, which causes the jellyfish to wash up on beaches when they swim too close.

Barrel jellyfish can grow to be about three feet long, but divers in the U.K. have documented seeing barrel jellyfish around five feet long. They have eight arms with stinging tentacles. Stings are typically not harmful to humans.

#4 Black Sea Nettle – Over 3.3 Feet

Black sea nettle jellyfish, Chrysaora achlyos, can have a bell size of over 3.3 feet in diameter. Its tentacles extend over eight feet and it can have oral arms up to 25 feet long. This jellyfish is rarely observed in nature and was not officially classified as a species until 1997. It has most recently been sighted off the coast of California.

The black sea nettle is often seen with the Pacific butterfish. The Pacific butterfish feeds on plankton collected by the jellyfish and hides in its large bell to avoid predators. Stings from this jellyfish can be painful but are not lethal to humans.

#3 Big Red Jellyfish – 2.6 to 4.9 Feet

Tiburonia granrojo, colloquially known as “big red” jellyfish, is a deep-sea invertebrate that can have a bell diameter of up to 4.9 feet. This jellyfish lives at depths of 2,000 to 4,900 feet. It can be found in the northeastern Pacific Ocean and the Pacific Ocean off the coasts of Japan, Hawaii, Mexico, and California.

The big red jellyfish uses its oral arms to propel itself through the water, unlike most jellyfish that pulsate their bells. It has long, thin tentacles that inject its prey with venom. Tiburonia granrojo was discovered as recently as 2003, and like many deep-sea creatures, much of its biology is still a mystery. What is known about big red jellyfish primarily comes from data collected using a remote-controlled vehicle.

#2 Nomura’s Jellyfish – 6.5 Feet

Nomura’s jellyfish, Nemopilema nomurai, are found in the waters of Japan, China, and Korea. They are commonly spotted in the Yellow Sea and East China Sea. They have a maximum bell size of around 6.5 feet and they can weigh as much as 440 pounds.

These jellyfish have eight arms with hundreds of tentacles that can reach over six feet long. Some sources estimate this jellyfish stings hundreds of thousands of people every year. Stings cause severe pain, swelling, and redness. Some stings have even resulted in shock or death.

#1 Lion’s Mane Jellyfish – 7 Feet

The lion’s mane jellyfish, Cyanea capillata, is thought to be the biggest jellyfish in the world. This jellyfish can grow to approximately seven feet in diameter. It has over a thousand tentacles in eight clusters of around 150 each. The tentacles can reach over 100 feet long.

These jellyfish are typically found in colder waters. They can be found in the Arctic and Antarctic regions, as well as the northern Atlantic, northern Pacific, and the North Sea. Despite their intimidating size, lion’s mane jellyfish stings are rarely fatal.