Some people say jellyfish are like colorful floating umbrellas. Well… floating sea umbrellas that can sting. These brainless invertebrates are among the deadliest and most resilient creatures on Earth. So far, 200 types of jellyfish are known, each one unique in color, size, and behavior. There is so much to learn about these fascinating creatures; in this article, we share curious facts about the different types of jellyfish.
Jellyfish belong to the order Cnidaria, which also includes other marine creatures like corals.
Granted, jellyfish are invertebrates, so we don't expect them to have bones or shells. However, you might not know that these marine creatures, also called sea jellies, also lack brains, blood, or hearts. Around 99% of the jellyfish’s body is water (the jelly in jellyfish), and just 1% is solid matter. Their bodies comprise a saucer, bell, bottle or boxed-shaped flexible dome, oral arms, a mouth, stomach, and tentacles.
Jellyfish don't live very long lives; most stay alive for only a few weeks. But some types of jellyfish survive for up to a year or more, and there is even the immortal jellyfish that can live forever. Some jellyfish species are no wider than an inch, while others can grow over 6 feet wide. Jellyfish are usually translucent, and some are bioluminescent (giving off light).
If you have ever been stung by a jellyfish, it was most probably an accident, and they weren't trying to eat or harm you. Jellyfish prefer to feed on algae, fish eggs, small fish, crustaceans, and even other jellies.
They capture their prey and defend themselves using their tentacles, which have stinging cells. The jellyfish sting occurs when the stinging cells, triggered by touch, eject tiny venomous barbs into the skin of a predator or prey.
We can find many different types of jellyfish in the world’s oceans, some living close to the surface and others at depths of over 1000 feet. Jellyfish have been to space and even have their own holiday; every November 3 is World Jellyfish Day.
Related: Have a read of our jellyfish quotes to see what other people have to say about these weird and wonderful sea creatures. We've also got a rundown of jellyfish facts to satisfy your curiosity about these wobbly sea creatures.
The moon jellyfish is one of the most common species of jellyfish, also, unsurprisingly, called the common jellyfish. We can find moon jellies in all oceans except the Arctic Ocean. They are most common along the coastal waters of North America and Europe.
Common jellyfish have translucent bodies with a pink or blue shade. The moon jellyfish has a dome diameter of 13 inches and four distinct circles in it, which are reproductive tissues. The moon jelly is bioluminescent and glows purple in the dark.
A moon jellyfish's sting is only mildly toxic to the human body but still hurts and might cause a rash. The moon jelly often falls prey to the leatherback turtle, ocean sunfish, bigger jellyfish, birds, and humans. Aurelia aurita has an average lifespan of 8 to 12 months in the wild and may not live past six months in captivity10.
Looking at this jellyfish from the top, it is pretty obvious where it gets its name from. It has a golden yellow circle on the center of its dome, and the surrounding part has a whitish opaque coloring. It looks like a cracked egg floating in the ocean. They also call it the Mediterranean jellyfish or egg yolk jellyfish.
The fried egg jellyfish can grow to be 16 inches wide. The free end of its oral arms and tentacles have purple and yellow tips. You probably won't feel a thing if you get stung by an egg yolk jellyfish. Their sting is mild enough that tiny fish and crabs freely hitch a ride on their bells or hide inside their tentacles.
These jellyfish inhabit the Mediterranean Sea, the Adriatic Sea, and the Aegean Sea. They stay alive for six months during the warmer months and die when the water begins to get colder.
The crystal jellyfish is a bioluminescent jellyfish that is almost entirely transparent when it is not glowing. When disturbed, crystal jellies emit a green light from the rim of their bells. This is what makes them so important to science. The crystal jellyfish is the source of the Green Fluorescent Protein that scientists use as cell markers.
It has a kind of flat bell that can get up to 7 inches in diameter but is just 4 cm high. Their bell is ringed with numerous stinging tentacles (up to 150) of varying lengths. These jellies have whitish radial canals that stretch from the mouth to the rim of their bells, which make them look like tiny bicycle wheels.
We find the crystal jellyfish living close to the shore of the North American, northern Alaska, and northern Mexico coasts. The crystal jellyfish eats other jellyfish and may be cannibalistic.
The lion’s mane jellyfish, or the arctic red jellyfish, is the largest type of jellyfish. They measure up to 8 feet in diameter and 120 feet in length. The lion’s mane jellyfish has a bell with eight lobes and about 150 tentacles trailing behind it. The color of their bells ranges from light orange to tan to deep orange and crimson red.
We find the lion’s mane jellyfish species in the colder Arctic5, North Atlantic, and North Pacific oceans. They are also present in the Gulf of Mexico. They live within the first 65 feet of the ocean’s surface, where they feed on other jellyfish in addition to small fish and zooplankton. A lion's manes venom and size do not protect them from predators like sea turtles, larger fishes, and birds.
The lion’ mane jellyfish lives for about a year. It is not uncommon to see a lion’s mane jellyfish washed ashore. That mainly occurs because when the jellyfish nears its life's end, it comes close to the shore, hiding in sheltered areas with other individuals. The tide often washes some of them ashore.
Considered the most venomous marine animal, the Australian box jellyfish sting is no joke9. It can cause paralysis, cardiac arrest, and death within a few minutes. This jellyfish, also called the sea wasps, is one of the box jellyfish species with venoms strong enough to kill humans.
Australian box jellyfish have box-shaped bodies that can be as wide as 1 foot, and their long tentacles can reach 10 feet. Their bell is transparent, and the tentacles have a light blue-grey hue. Australian box jellies, found in the waters of Southeast Asia and Australia, have eyes; they are one of the few that do.
In captivity, the sea wasp stays alive for nine months tops. In the wild, they live for about a year and die soon after reproducing. Because of its venom, the sea wasp doesn't have many predators, except the green sea turtle that preys on them since the venom can not penetrate through its thick skin.
The mangrove box jellyfish live in coastal mangrove forests, normally between the roots of the trees. You can find them in Central America from Florida, Puerto Rico, the Caribbean, the Gulf of Mexico, and the Atlantic Ocean.
This box jellyfish is roughly the size of a grape, 0.5 inches in diameter, and about 1-inch bell length. The mangrove box jellyfish has 24 eyes, grouped into four clusters. In each cluster, two eyes look very much like human eyes.
Although we know some box types of jellyfish to have highly venomous stings, the mangrove box jellyfish stings harmlessly. Humans, however, threaten the existence of this box jellyfish; they are clearing mangrove forests for agriculture and building construction.
The mushroom cap jellyfish has a dense and thick bell, shaped like a mushroom cap, with a diameter of up to 20 inches. It doesn't have tentacles but has eight thick oral arms with finger-shaped appendages. The color of the bell ranges from creamy white to pale yellow, pink, or green. The oral arms usually have brown markings on the free ends.
Although they lack stinging tentacles, these jellies have stinging cells within their bells that can deliver a mild sting to humans. Also called the sea mushroom jellyfish, people who eat jellyfish consider this jellyfish species a delicacy in Japan and China.
The cannonball jellyfish closely resembles the mushroom cap jelly, and they are often confused as the same. However, the mushroom cap jelly grows bigger than the cannonball jelly and has finger-shaped oral arms, which the cannonball jellyfish lacks.
The Irukandji jellyfish is very tiny; at its largest, it is no wider than 2.5 cm. Despite its size, it packs a punch with its venom. The venom of the Irukandji jellyfish can cause headaches, vomiting, cardiac arrest, brain bleeds, or even death, amongst many other things. It has four retractable tentacles, each one at the corners of its bell.
The Irukandji jellyfish's tentacles and bells are covered with stinging cells, although the cells on the tentacles are different. They can poison and eat small marine vertebrates, which is impressive because they are very tiny themselves. They have primitive eyes on every side of their bell.
We can find this type of jellyfish species along the coastline of northern Australia, about 65 feet below the sea surface. They swim pretty fast and are noted for their agility.
The bloody-belly comb jellyfish is a deep-sea organism that lives at depths of 980 to over 3000 feet. We can find them in oceans in Canada, southern California, and Japan. The jellyfish grows to about 6 inches in length and has no tentacles1.
Like all comb jellies, the bloody-belly jellyfish has eight rows of combs, a structure with hair-like tissue arranged like teeth on a comb. They use these combs for swimming and eating. Their luminous and sparkling rows of combs make it unique among other comb jellies.
The color of this comb jelly ranges from deep red, purple, black, or pale purple. It could even be transparent, but its stomach is always deep red. This is because the color red is invisible in the deep sea and against the ocean floor, and so when this jellyfish captures a bioluminescent prey in its stomach, the glow of the prey is concealed. This feature helps to hide the jellyfish from predators.
The cannonball jellyfish is also called the cabbage head jellyfish. It has a super thick and rounded bell that is usually about 5 inches in length and 7 to 10 inches wide. The bell can be milky white or pale yellow with or without a speckled brown rim.
These types of jellyfish have no tentacles but have 16 short oral arms. The arms have secondary mouth folds that secrete venomous mucus for trapping small prey or driving away predators2. That is where its scientific name is pulled from, ‘Stomolophus meleagris,’ which means “many-mouthed hunters.”
We find them in the Pacific and Atlantic Oceans, and they are also particularly abundant on the Gulf Coast. Cannonball jellyfish usually die within six months, primarily due to predators. These are fast swimmers; they can turn their bodies upside down and swim rapidly downwards when attacked.
Also called the alarm jellyfish, crown jellyfish, or coronate medusa, this type of jellyfish is a deep sea species that is surely interesting to look at. If you view it from the top, it looks like a floating iris with tentacles; from a side view appears like a crown. It has 20 tentacles, one growing longer than the rest. The bell is just 6 inches wide.
The coronate jellyfish live in the ocean's midnight zone, about 13,000 feet deep. The atolla jellyfish has a deep red coloration that helps it appear invisible. However, it is also bioluminescent.
These jellyfish flash a bright blue light to disorient or attract prey. The flashing lights also dazzle predators or attract even bigger predators, like different types of sharks, that would be more interested in the original attacker. The atolla jellyfish can then escape in the ensuing scuffle.
The pink meanie jellyfish is bright blush pink jelly. This beautiful but deadly jellyfish likes to feed on other jellies. The moon jellyfish happens to be its favorite snack. Perhaps their predatory inclination is what earned them the ‘meanie’ in their name.
This jellyfish has hundreds of tentacles that sting, and it hunts by spreading them out. As soon as a few tentacles touch prey, the pink meanie jellyfish deploys more tentacles to pull them in. They have oral arms that secrete digestive juices for breaking down their food.
The pink meanie can trap prey bigger than it or multiple prey simultaneously. One pink meanie jelly had been seen with 34 moon jellies in its tentacles. Pink meanie jellies keep growing until they die, so they can be a few inches or several feet wide. They usually live for one year, dying soon after breeding.
We also call this jellyfish species blue bottle jellyfish or Pacific man o war. You'll find them in the warm waters of the northern Atlantic Ocean’s Gulf Stream, the Sargasso Sea, the Pacific Ocean, and the Indian Ocean. They typically float on the water's surface or just beneath it.
Named for its similarity to an 18th-century warship, the Portuguese man o war has a float or air bladder filled with carbon dioxide. The bottle-shaped float has a crest that works like a sail for navigation. The float is usually about 11 inches long, and the tentacles can be up to 98 feet long.
The Portuguese man o war is not a true jellyfish type. Each individual is a colony of unisexual polyps. The float, the tentacles, the digestive tracts, and the reproductive parts are actually four different organisms3.
They work together and so mimic true jellyfish. The sting of the Portuguese man o war is fatally venomous, and the tentacles can still sting even after the jelly has been washed ashore for weeks.
From its name, you can already guess that this jellyfish is a feared stinging jellyfish4. They are small jellyfish, the adults measuring 12 cm at most, but they have about eight wispy, thin, 10-foot-long tentacles. They have elastic oral arms, too.
Another name for mauve stingers is purple jellyfish. They have an inky purple bell dotted with brownish-red spots. Not only do mauve stingers have a soft purple glow, but they also release glowing mucus when they are startled. Little wonder their scientific name means ‘night light’ in German.
Mauve stingers feed on small fish and crustaceans, and their stingers can even pierce the shell of a crab. To humans, the sting usually causes a very painful sting that leaves a scar. These jellyfish don't live for very long and die within 2 to six months.
The immortal jellyfish can seemingly escape from death and live forever. When injured or starving, these jellyfish can return to their baby jellyfish stage7 (polyps that look a bit like sea anemones). While most jellyfish species don't live beyond a year, a single immortal jelly may very well have been alive since the time of dinosaurs. They really only die if they get eaten.
Immoral jellies are very tiny, just about 0.18 inches in diameter. They have bright red stomachs visible through their transparent bell. They have about 90 tentacles around the edge of their bell.
Turritposis dohrnii is an invasive species. They are known to attach themselves to ships and colonize new areas. They call these jellyfish the silent invaders of the ocean; they are showing up everywhere in great numbers.
The flower hat jellyfish is a truly striking creature. It has a translucent bell lined with dark pinstripe growths. The stripes grow into tentacles with brightly colored, bioluminescent ends. It has another set of springy tentacles for feeding around the bell. The flower hat jellyfish is about 6 inches wide.
Flower hat jellies live in the shallow coastal waters of the Atlantic Ocean and Pacific Oceans at depths of up to 180 feet. During the day, they remain close to the sea floor. They float to the water surface at night to forage for food.
Flower hat jellyfish sting is so painful that they leave you with a bright red rash. Usually, they are solitary hunters, but they can be very harmful when they form blooms. Not only does this type of jellyfish hurt fishing, but they can also clog power plant ducts. They can even sting a human to death.
This jellyfish is also called the white-spotted jellyfish, the floating bell, or the brown jellyfish. They are native to the western Pacific Ocean but have invaded waters elsewhere.
While spotted jellyfish have voracious appetites, their enormous appetite for zooplankton and fish, shrimp, and crab larvae threatens the ecological balance of the waters they invade.
The white spotted jellyfish have a somewhat transparent bell dotted with white reflective spots. They grow to be about 20 inches wide and have no tentacles but oral arms with stinging cells. The sting is mild and not harmful to humans.
The black sea nettle does not have a black but deep purple bell, which can be as wide as 3 feet. The bell color gets lighter towards the edge. It has pinkish oral arms that grow to about 29 feet, and its tentacles can grow to over 25 feet.
Scientists only recently described the black sea nettle in 19978, famously the largest invertebrate discovered in the 20th century. Black sea nettles bloom periodically and are rarely seen. The few times the black sea nettle jellyfish have been seen have occurred during red tides.
The black sea nettle jellyfish provides food and protection to the Pacific butterfish. The butterfish feeds on plankton that the jellyfish gathers, and when danger approaches, they hide in its stomach.
The upside-down jellyfish is a truly interesting creature. They spend all their time with their bells downward. Their oral arms are pointed toward the sun so the algae in their tissue can photosynthesize and provide energy. Turned up that way, they look like pretty sea plants.
The jellyfish has a brown or blue-grey bell that grows up to 14 inches. The bell has an indent in the center that helps it balance on the ground. This indent probably makes it easy for the water crabs to carry the jellyfish on their backs and use them as protection.
They release mucus with stinging cells to catch prey, which is moderately painful to humans. These jellies are endangered because they live in mangrove forests and shallow lagoons, areas that are the target of commercial development.
The cauliflower jellyfish is also called the crown jellyfish, just like the atolla jelly, but they couldn't look more different. The cauliflower jellyfish has a bluish-purple bell that is usually about 5 inches but can grow up to 19 inches. On top of the bell is a protruding ball with wart-like growths. It looks very much like a small cauliflower vegetable.
Like many deep sea jellyfish, the cauliflower jellyfish is bioluminescent and uses it to save itself when attacked by a predator.
The jellyfish's brown oral arms are almost joined at the base but branch into forked branches. They also have many long, thin tentacles. They feed on fish eggs, shrimp, algae, and plankton. Although the cauliflower has venom deadly to its prey, it is harmless to humans. It is so harmless that people in some parts of Asia eat this crown jellyfish.
The narcomedusae jellyfish was described only recently6, in 2010. It is a deep-water jellyfish of the arctic ocean, living at depths of 1.400 to 2000 meters. It has earned the nickname Darth Vader jellyfish because its bell is shaped like the character’s helmet.
This jellyfish species has a transparent bell and whitish stomach chambers. It has four primary tentacles and four very short secondary tentacles. The jellyfish swims with its tentacles forward rather than trailing behind the bell. Narcomedusae jellies grow to be less than an inch.
Unlike other types of jellyfish, the Darth Vader jellyfish babies grow inside them. After a baby is born, it will attach itself to another jellyfish for protection and nutrition.
Jellyfish are possibly the most mysterious sea creatures, and learning about them is fascinating. Although over 200 species are known, thousands more may be waiting to be discovered.
Harbison, G. Richard, Matsumoto, George I., Robison, Bruce H., (2001). Lampocteis cruentiventer gen. nov., sp. nov.: A new mesopelagic lobate ctenophore, representing the type of a new family (Class Tentaculata, Order Lobata, Family Lampoctenidae, fam. nov.). Bulletin of Marine Science, 68: 299-311.
Li, R., Yu, H., Xue, W., Yue, Y., Liu, S., Xing, R., & Li, P. (2014). Jellyfish venomics and venom gland transcriptomics analysis of Stomolophus meleagris to reveal the toxins associated with sting. Journal of Proteomics, 106, 17-29.
Tiralongo, Francesco & Badalamenti, Rosario & Arizza, Vincenzo & Prieto, Laura & Lo Brutto, Sabrina. (2022). The Portuguese Man-of-War Has Always Entered the Mediterranean Sea-Strandings, Sightings, and Museum Collections. Frontiers in Marine Science. 9. 10.3389/fmars.2022.856979.
Mariottini, G. L., Giacco, E., & Pane, L. (2008). The mauve stinger Pelagia noctiluca (Forsskål, 1775). Distribution, ecology, toxicity and epidemiology of stings. A review. Marine drugs, 6(3), 496-513.
Doyle, T. K., Headlam, J. L., Wilcox, C. L., MacLoughlin, E., & Yanagihara, A. A. (2017). Evaluation of Cyanea capillata sting management protocols using ex vivo and in vitro envenomation models. Toxins, 9(7), 215.
Raskoff, Kevin. (2010). Bathykorus bouilloni: A New Genus And Species Of Deep-Sea Jellyfish From The Arctic Ocean (Hydrozoa, Narcomedusae, Aeginidae). Zootaxa. 2361. 57-67. 10.5281/zenodo.193628.
Matsumoto, Y., Piraino, S., & Miglietta, M. P. (2019). Transcriptome characterization of reverse development in Turritopsis dohrnii (Hydrozoa, Cnidaria). G3: Genes, Genomes, Genetics, 9(12), 4127-4138.
Martin, J. W., Gershwin, L. A., Burnett, J. W., Cargo, D. G., & Bloom, D. A. (1997). Chrysaora achlyos, a remarkable new species of scyphozoan from the Eastern Pacific. The Biological Bulletin, 193(1), 8-13.
Brinkman DL, Aziz A, Loukas A, Potriquet J, Seymour J, Mulvenna J (2012) Venom Proteome of the Box Jellyfish Chironex fleckeri. PLoS ONE 7(12): e47866. https://doi.org/10.1371/journal.pone.0047866
Miyake, H., Iwao, K., & Kakinuma, Y. (1997). Life history and environment of Aurelia aurita (pdf). South Pacific Study, 17(2), 273-285.
Jen’s a passionate environmentalist and sustainability expert. With a science degree from Babcock University Jen loves applying her research skills to craft editorial that connects with our global changemaker and readership audiences centered around topics including zero waste, sustainability, climate change, and biodiversity.
Elsewhere Jen’s interests include the role that future technology and data have in helping us solve some of the planet’s biggest challenges.