26 Different Types of Jellyfish in the Ocean

Different types of jellyfish species

Jellyfish are among the oldest species that have evolved and lived on Earth. Hence, it is no surprise that we now have thousands of species of jellyfish, with some still not yet fully documented.

If you want to learn about the common types of jellyfish you can encounter in the open ocean, stick around! We’ve listed 26 types of jellyfish species and discussed their unique characteristics and specific behaviors.

26 Types of Jellyfish Species

1. Moon Jellyfish

Moon Jellyfish
Scientific Name:Aurelia aurita
Common Names:Moon Jellyfish, Saucer Jellyfish
Habitat:Coastal waters
Size:40–60 cm in diameter
Sting Severity:Mild
Unique Features:Translucent with four horseshoe-shaped gonads visible in its bell; some species are bioluminescent.

The Moon Jellyfish is a unique sea creature often seen in coastal waters worldwide. Their name comes from the moon-like, translucent bell that can grow up to 40 to 60 centimeters in diameter.

Unlike other jellyfish with long tentacles, Moon Jellies have short ones that help them feed by sweeping food toward a mucus layer on their bell’s edge.

One of the most striking features of Moon Jellies is the four horseshoe-shaped gonads visible through their bell. These reproductive organs usually appear purple, adding to the jellyfish’s alien-like appearance.

Like other jellyfish species, Moon Jellies comprise 95% water and lack complex organs like a brain or heart, relying on a simple network to navigate and feed.

They have a two-stage life cycle, starting as polyps that attach to rocks and then developing into the medusa stage, the free-floating form we recognize.

Watch this fascinating video showing a massive bloom of Moon Jellies:

A Jellyfish Explosion | Alaska's Deadliest

Fun Fact: Even though Moon Jellyfish haven’t been to the moon, they already had a trip to space in 1991!

Moon Jelly polyps and ephyrae, the early life stages of these jellyfish, were sent aboard a space shuttle to study how weightlessness affects their development.

2. Lion’s Mane Jellyfish

Lions Mane Jellyfish
Scientific Name:Cyanea capillata
Common Names:Lion’s Mane Jellyfish
Origin:Cooler regions of the Pacific and Atlantic region
Habitat:Cold, temperate, subtropical waters
Size:Up to 3 m in diameter; up to 30 m in tentacle length
Sting Severity:Moderate 
Unique Features:Largest species of jellyfish; long, hair-like tentacles

The Lion’s Mane Jellyfish is the largest known jellyfish species. They can be found in the colder regions of the Pacific and Atlantic Oceans.

These jellyfish are easily distinguishable by their large, bell-shaped bodies and many thin, hair-like tentacles resembling a lion’s mane​​.

Their bell typically spans up to 3 meters across. With tentacles extending more than 30 meters long, they can be longer than a blue whale, the largest mammal on Earth.

The Lion’s Mane Jellyfish’s “mane” consists of up to 1,200 tentacles divided into eight clusters.

Each tentacle is equipped with nematocysts containing a potent neurotoxin for capturing prey. This sting, while very toxic, has rarely been reported to cause human fatalities.

Their diet mainly consists of small fishes, tiny crustaceans, and even other jellyfish. These solitary swimmers can travel great distances and occasionally gather in large swarms during storms and tides​​​​.

Fun Fact: The Lion’s Mane Jellyfish was featured as a murder weapon in the famous short story by Arthur Conan Doyle, “ The Adventure of the Lion’s Mane.”

3. Australian Box Jellyfish

Australian Box Jellyfish in South Africa
Scientific Name:Chironex fleckeri
Common Names:Box Jellyfish, Australian Box Jellyfish, Sea Wasp
Origin:Indo-Pacific region; primarily in Northern Australia and Southeast Asia
Habitat:Coastal waters of the Pacific and Indian Oceans
Size:Up to 30 cm in diameter; up to 3 m in tentacle length
Sting Severity:Severe (potentially lethal)
Unique Features:Cube-shaped bell; extremely venomous tentacles

The Australian Box Jellyfish is an intriguing yet dangerous marine creature primarily found in the warm coastal waters of the Indo-Pacific region.

Known for their distinctive cube-like bell, they are the largest among the box jellyfish species, with a bell diameter of up to 30 centimeters and tentacles stretching up to three meters long​​.

These jellyfish have earned a reputation for their highly potent venom, among the deadliest in the world.

Their venom contains toxins that target the heart, nervous system, and skin cells, causing extreme pain and potentially fatal consequences like heart failure or drowning due to shock in human victims.

The stings of Box Jellyfish are so severe that they have been responsible for numerous deaths​​.

4. Irukandji Jellyfish

Irukandji Jellyfish
Image credit: the_daily_kraken / Instagram
Scientific Name:Carukia barnesi
Common Names:Irukandji Jellyfish
Origin:Primarily found in Northern Australia but can be found worldwide
Habitat:Coastal waters
Size:Up to 2 cm in diameter
Sting Severity:Severe (potentially lethal)
Unique Features:Smallest jellyfish; extremely venomous; causes Irukandji syndrome

The Irukandji Jellyfish is a small yet extremely venomous marine creature. Measuring up to just two centimeters in diameter, these jellyfish are almost invisible in the water, making them a hidden hazard. They are known for their potent venom.

Irukandji are primarily found in the coastal waters of Northern Australia but have a global presence, including popular destinations like Southeast Asia, the Caribbean, and the United Kingdom.

Despite their size, the danger they pose is grave. Irukandji stings can lead to a severe condition known as Irukandji Syndrome, marked by excruciating pain, vomiting, difficulty breathing, and, in some cases, fatality.

5. Portuguese Man o’ War

Portuguese Man oWar
Scientific Name:Physalia physalis
Common Names:Portuguese Man o’ War, Portuguese Man-of-War, Bluebottle Jellyfish, Pacific Man o’ War
Habitat:Open ocean
Size:Up to 30 cm wide; up to 50 m in tentacle length
Sting Severity:Moderate to Severe
Unique Features:Not a true jellyfish; a floating colony of polyps

The Portuguese Man o’ War, known scientifically as Physalia physalis, is a unique marine creature often mistaken for a jellyfish. In reality, they are siphonophores, colonial organisms composed of many smaller units called zooids that work together as one.

The most recognizable part of these jellyfish is the pneumatophore, a gas-filled bladder that floats above the water, acting as a sail and giving it its warship-like appearance.

This structure allows Man o’ Wars to travel vast distances, driven by wind, waves, and marine currents​​.

The tentacles, or dactylozooids, can extend up to 50 meters and are equipped with venomous nematocysts, which are used to paralyze and kill fish and other small creatures.

While a sting to humans is excruciatingly painful, it is rarely deadly. Notably, even dead Man o’ Wars washed up on shore can still deliver a sting​​.

Portuguese Man o’ Wars have no means of propulsion and move passively, relying on the ocean’s winds, currents, and tides for movement. They are often found in large groups and can be seen stranded on beaches​​.

This is what my family witnessed while taking a week-long vacation on one of the beaches in Australia. Toward the latter part of our stay, authorities informed us that all beaches had been closed temporarily. 

This was due to a sizeable swarm of Bluebottle Jellies being pushed ashore by strong waves. Though our vacation was cut short, the closure was a great decision to prevent any possible harm to humans. 

Curious how the Portuguese Man o’ War catches its prey? Watch this video:

The Deadly Portuguese Man O' War | Blue Planet II | BBC Earth

6. Compass Jellyfish

Compass Jellyfish
Scientific Name:Chrysaora hysoscella
Common Names:Compass Jellyfish
Origin:Northeast Atlantic
Habitat:Coastal waters
Size:15–30 cm in diameter
Sting Severity:Moderate
Unique Features:Brown or yellow with V-shaped patterns

The Compass Jellyfish is a distinctive species of jellyfish found in coastal waters. They are easily identifiable by their unique bell, which typically features 16 brown, V-shaped markings on a translucent yellow-white body.

These markings, surrounding a central brown spot, give the appearance of a compass face, hence their common name. These jellyfish’s bell can reach up to 30 cm in diameter, providing a significant presence in the water​​​​​​.

These jellyfish are commonly found in the Atlantic and Mediterranean regions, including waters near the United Kingdom and Turkey. They are also present in the southern Atlantic Ocean near the west coast of South Africa.

They are notable for their 24 tentacles, which are organized in eight groups of three and four long, frilled oral arms that extend from the manubrium. These tentacles and arms are crucial for capturing prey and feeding​​​​.

7. Mauve Stinger

Mauve Stinger
Scientific Name:Pelagia noctiluca
Common Names:Mauve Stinger, Purple Stinger
Origin:Found globally in warm temperate and tropical waters
Habitat:Open ocean
Size:Up to 12 cm in bell diameter; up to 3 m in tentacle length
Sting Severity:Moderate
Unique Features:Bioluminescent; pink, purple, or mauve in color

The Mauve Stinger is a small but notable jellyfish species. Their bell diameter ranges up to 12 centimeters, with their color varying from mauve, purple, pink, and light brown to yellow​​.

This variety in color, combined with their bell’s mushroom shape and nematocyst-bearing warts on their surface, adds to their distinctive appearance.

Mauve Stingers are efficient predators equipped with eight thin, stinging tentacles and four oral arms. Their tentacles are used to catch prey, which they transport to their mouth via the oral arms.

Mauve Stingers are found in warm, temperate, and tropical waters globally. They are known for their painful sting and ability to form large blooms, which can cause significant ecological impacts.

In 2007, a massive bloom of Mauve Stingers caused extensive damage to penned salmon at a fish farm in Ireland, highlighting the potent nature of their sting and their impact on marine life​.

8. Purple-striped Jellyfish

Purple striped Jellyfish
Scientific Name:Chrysaora colorata
Common Names:Purple-striped Jelly
Origin:Pacific coast of North America, especially off the coast of California
Habitat:Primarily open ocean; also found in coastal bays and estuaries
Size:Bell diameter up to 70 cm; tentacles several meters long
Sting Severity:Moderate
Unique Features:Vibrant purple stripes radiating from the center of a translucent bell

The Purple-striped Jellyfish is a visually striking marine creature found primarily on the Pacific coast of North America.

Adults of these species are notable for their silvery white color with deep purple bands, which juveniles lack​. Their bells can grow up to 70 centimeters in diameter.

These jellyfish are typically open-ocean dwellers but are known to venture near the shores occasionally, especially in certain seasons.

Despite their enchanting appearance, it’s advised to maintain a safe distance due to their potent sting​​​​.

Fun Fact: Purple-striped Jellyfish have a unique ecological relationship with young cancer crabs (Cancer gracilis). These crabs are often found clinging to the Purple-striped Jellies and eat parasitic amphipods.

9. Blue Blubber Jellyfish

Blue Blubber Jellyfish
Scientific Name:Catostylus mosaicus
Common Names:Blue Blubber Jellyfish, Blubber Jelly
Origin:East Coast of Australia; Indo-Pacific region
Habitat:Found in harbors, estuaries, and open water; typically in the middle to surface of the water column in shallow areas
Size:Up to 40 cm wide in bell diameter
Sting Severity:Mild
Unique Features:Displays a range of colors (white, blue to dark purple, burgundy) due to symbiotic algae. Notable for its distinctive, staccato-like bell pulse.

The Blue Blubber Jellyfish is commonly found in the coastal waters of eastern and northern Australia but also inhabits regions in the Indo-Pacific.

Contrary to their name, these species showcase a vibrant spectrum of colors, including light blue, dark purple, and burgundy, due to symbiotic algae inside their body.

The bell of these jellyfish, reaching up to 40 centimeters in diameter, is notable for its unique staccato-like pulsations, which assist in locomotion.

Predominantly inhabiting coastal lagoons and open ocean waters, Blue Blubber Jellyfish often form large blooms.

They feed primarily on zooplankton, capturing their prey using stinging cells on their oral arms. They are also known to eat small crustaceans and fish larvae.

Blue Blubber Jellyfish have developed interesting ecological relationships. They are sometimes associated with small fish and crustaceans like copepods, which may consume the mucus produced by the jellyfish. 

Despite their stinging cells, their sting is generally mild and not considered a significant risk to humans.

Fun Fact: Blue Blubber Jellyfish is a culinary specialty in some cultures, especially in Asia!

10. Nomad Jellyfish

Nomad Jellyfish
Scientific Name:Rhopilema nomadica
Common Names:Nomad Jellyfish
Origin:Indigenous to the tropical warm waters of the Indian and Pacific Oceans; also found in the Mediterranean Sea
Habitat:Thrives in warm waters, adaptable to various temperatures 
Size:40–60 cm in diameter
Sting Severity:Severe
Unique Features:Light blue body with a rounded bell; Forms large swarms, causing socioeconomic problems and impacting recreational beaches.

The Nomad Jellyfish is another distinctive species primarily found in the warm tropical waters of the Indian and Pacific Oceans.

Since the 1970s, they have expanded their range to the Mediterranean Sea through the Suez Canal, a process known as Lessepsian migration.

These jellyfish are notable for their light blue bodies and rounded bells, which can grow to impressive sizes, commonly up to 40 to 60 centimeters in diameter.

Behaviorally, Nomad Jellyfish are known for forming large swarms, especially during the summertime. These swarms can cause considerable problems, such as clogging seawater intake systems in power plants.

The stings of these jellyfish are painful and have led to the highest number of envenomations along the southern Levant coast.

11. Cannonball Jellyfish

Cannonball Jellyfish
Scientific Name:Stomolophus meleagris
Common Names:Cannonball Jellyfish, Cabbage-head Jellyfish
Origin:Found in the southeastern United States, the Gulf Coast, the western and eastern Pacific, and the western Atlantic
Habitat:Typically found in estuaries and saline water, usually by the shoreline, in warm waters worldwide
Size:Up to 25 cm in diameter
Sting Severity:Mild
Unique Features:Distinctive rounded bell shape; oral arms with poisonous stinging cells; and ability to shrink size

These jellyfish are also referred to as the Cabbage-head Jellyfish due to their unique appearance. They are well-known for their distinctive rounded bell shape, often likened to a cannonball or cabbage when curled up.

Their bell’s diameter can reach up to 25 centimeters, and their rims are typically covered with brown pigments.

Cannonball Jellyfish have oral arms with tentacles containing poisonous stinging cells, which they use for catching prey and aiding in propulsion. Notably, their sting is generally mild for humans.

One of the most remarkable behaviors of Cannonball Jellyfish is their ability to shrink their size. This shrinking behavior is a defensive mechanism that makes them less detectable to predators.

Fun Fact: Besides their stinging cells and shrinking abilities, Cannonball Jellyfish can also secrete a toxic mucus to deter would-be predators.

12. Flower Hat Jelly

Flower Hat Jelly
Scientific Name:Olindias formosa
Common Names:Flower Hat Jelly
Origin:Northwestern Pacific, primarily off central and southern Japan, South Korea​
Habitat:Typically resides near the ocean floor among rocks or algae, with nocturnal hunting behavior
Size:Up to 15 cm in diameter
Sting Severity:Moderate
Unique Features:Translucent, pinstriped bell with lustrous, mathematically arranged tentacles; appears fluorescent due to proteins

Similar to the Portuguese Man o’ War, the Flower Hat Jellyfish is another species that is called jellyfish but isn’t a true jellyfish species. They belong to the Hydrozoa class, whereas true jellyfish are part of the Scyphozoa class.

Renowned for their stunning appearance, Flower Hat Jellyfish showcase a translucent bell marked with pinstripes and vibrant, fluorescent-tipped tentacles.

These tentacles are uniquely arranged in a mathematical Fibonacci pattern and can coil around the jelly’s rim, adding to their intriguing look. Flower Hat Jellies have a sting that, while generally mild, can cause a painful rash.

These species are nocturnal, spending daytime hours near the ocean floor, amidst rocks or algae, and surfacing at night to hunt small fish.

13. Black Sea Nettle

Black Sea Nettle
Scientific Name:Chrysaora achlyos
Common Names:Black Sea Nettle, Black Jellyfish
Origin:Found in the Pacific Ocean off North America, ranging from Monterey Bay to southern Baja California and Mexico​
Habitat:Ocean waters
Size:Up to 1 m in diameter; oral arms extend up to 6 m while tentacles can reach over 2 m
Sting Severity:Severe
Unique Features:Notable for its massive size, distinctive dark purple to nearly black bell coloration; carnivorous diet, mainly feeding on zooplankton and other jellyfish

The Black Sea Nettle Jellyfish is a fascinating and relatively new discovery in the marine world. Identified as a distinct species only in 1997, their rarity and preference for deep, calm waters make them elusive creatures.

These jellyfish stand out for their impressive size, with a bell diameter reaching one meter, tentacles stretching over two meters, and oral arms extending up to six meters.

Black Sea Nettles are also notable for their striking colors. The bell of mature specimens is typically purple to black, while younger and smaller nettles display reddish to maroon hues.

Their bell’s rim is adorned with a unique pattern of light brown to tan specks. In terms of these jellyfish’s diet, they prey on various marine life, including copepods, larval fishes, planktonic crustaceans, and other jellies.

One intriguing aspect of Black Sea Nettles is their symbiotic relationship with larval and juvenile crabs and the Pacific Butterfish.

These creatures travel with the jellies, benefiting from their protection and feeding on detritus-laden mucus from the jelly’s oral arms.

14. White-spotted Jellyfish

White spotted Jellyfish
Scientific Name:Phyllorhiza punctata
Common Names:White-spotted Jellyfish, Floating Bell, Australian Spotted Jellyfish, Brown Jellyfish
Origin:Native to the western Pacific from Australia to Japan
Habitat:Prefers warm temperate seas, aggregates in waters near coastlines
Size:50–70 cm in bell diameter
Sting Severity:Mild
Unique Features:Notable for their mild venom, which is not potent enough to kill prey, leading them to be filter feeders primarily consuming zooplankton

The White-spotted Jellyfish originated from the western Pacific but is now found globally, often near coastlines in warm temperate seas.

These jellyfish are recognizable by their large, translucent bell, which can grow up to 70 centimeters in diameter and are adorned with distinctive white spots.

Despite their size, White-spotted Jellyfish are relatively harmless to humans, thanks to their mild venom. Their sting typically causes little to no discomfort and can be easily treated.

Nevertheless, these species are notable for their significant ecological impact. As filter feeders, they consume vast amounts of zooplankton, which can disrupt local ecosystems by depleting food sources for other marine life.

15. Barrel Jellyfish

Barrel Jellyfish
Scientific Name:Rhizostoma pulmo
Common Names:Barrel Jellyfish, Dustbin-lid Jellyfish, Frilly-mouthed Jellyfish
Origin:Found in the northeast Atlantic, including the Adriatic, Mediterranean Sea, Black Sea, Sea of Azov, and off the western South African coast
Habitat:Prefers warm temperate waters.
Size:50–90 cm in bell diameter
Sting Severity:Mild
Unique Features:Recognized as one of the largest jellyfish in British and Irish waters; notable for its ability to grow exceptionally large

The Barrel Jellyfish stands out due to its impressive size. It’s commonly found in the eastern Atlantic, the Mediterranean, and the Black Sea, thriving in open waters.

These jellyfish are one of the largest in British and Irish waters, with their bells reaching up to 90 cm in diameter and larger specimens being even more massive.

Despite their size, Barrel Jellyfish’s sting is moderately venomous and generally not a serious threat to humans. It can cause skin irritation, lesions, and ulcers, but these effects are relatively mild compared to other jellyfish.

Barrel Jellyfish play a significant role in its ecosystem, especially noted for forming large blooms in response to higher temperatures, a phenomenon increasingly observed with global warming.

16. Upside-down Jellyfish

Upside down Jellyfish
Scientific Name:Cassiopea xamachana
Common Names:Upside-down Jellyfish, Cassiopea Jellyfish
Origin:Indo-Pacific Ocean, the Caribbean, Southern Florida, and Hawaii 
Habitat:Shallow, tropical marine waters; commonly found on sandy mudflats and mangrove leaves​
Size:Up to 30 cm in bell diameter
Sting Severity:Mild
Unique Features:Notable for being among the jellyfish species that benefit from photosynthesis; can produce venom-filled mucus

The Upside-down Jellyfish is a unique marine creature, often found in shallow, tropical waters, particularly among mangrove leaves. Unlike most jellyfish, they spend most of their lives upside-down on the ocean floor.

This positioning optimizes the sunlight exposure for their symbiotic algae, zooxanthellae, which live in their tissues and give them a distinct green or blue coloration.

Upside-down Jellyfish host these algae within their bodies. In exchange, these algae share the nutrients they produce through photosynthesis.

These jellyfish are also famous for their unconventional defense mechanism: releasing mucus blobs with stinging cells. These blobs can sting prey or deter predators without direct contact, causing an itchy-to-burning sensation in humans.

I once witnessed the bizarre behavior of Upside-down Jellies in Florida. We saw a swarm of these jellyfish almost synchronously, gently pulsing upside-down near the surface water to maximize the light they get.

It was a mesmerizing sight, especially as I realized they do this for the mutual benefit of the algae they host.

17. Atlantic Sea Nettle Jellyfish

Atlantic Sea Nettle Jellyfish
Scientific Name:Chrysaora quinquecirrha
Common Names:Atlantic Sea Nettle Jellyfish
Origin:Found in the Atlantic and Indian Oceans, as well as the Western Pacific​
Habitat:Inhabits temperate waters and Atlantic estuaries, which are low in salinity
Size:10–25 cm in bell diameter
Sting Severity:Mild
Unique Features:Notable for its opaque white body with red streaks or dots

The Atlantic Sea Nettle Jellyfish is a fascinating marine creature found in tepid waters along the Atlantic and Indian Oceans, including the Western Pacific.

These species are characterized by their opaque white body, often adorned with red streaks or dots. Their unique lifecycle includes a sessile polyp stage and a mobile medusa stage.

The bell of the Atlantic Sea Nettles can vary in size depending on the location. Those that live in the open ocean can grow up to 25 centimeters, while those on bays and estuaries are typically 10 centimeters.

While their sting can be painful and may cause severe reactions in sensitive individuals, the toxin it carries is relatively mild.

These jellyfish are a vital part of the marine ecosystem, serving as prey for creatures like sea turtles and other jellyfish.

18. Cross Jellyfish

Cross Jellyfish
Scientific Name:Mitrocoma cellularia
Common Names:Cross Jellyfish, Northern Cross Jellyfish
Origin:North Pacific Ocean, in cooler, temperate waters
Habitat:Coastal and estuarine areas, ranging from shallow to deeper ocean waters
Size:Up to 9 cm in bell diameter
Sting Severity:Mild
Unique Features:Translucent bell with a distinctive cross pattern, bioluminescent, short tentacles

The Cross Jellyfish is a notable marine species easily recognized by its unique cross-shaped structure, formed by four canals originating from its stomach.

Their bell, measuring around nine centimeters in diameter, is adorned with hundreds of delicate white tentacles.

Cross Jellyfish often appear near the shore and can sometimes be seen in large groups. They are found primarily in the photic zone of waters from northern Alaska to central California.

These species are known for their bioluminescence, emitting a glow when disturbed, adding an element of intrigue to their already fascinating appearance.

Recent research suggests that the Cross Jellyfish may be able to sense their prey. This capability implies that the jellyfish may actively pursue food sources rather than passively drifting and relying on chance, unlike other jellyfish species.

19. Fried Egg Jellyfish

Fried Egg Jellyfish
Scientific Name:Cotylorhiza tuberculata
Common Names:Fried Egg Jellyfish
Origin:Eastern Pacific Ocean, Mediterranean Sea, sometimes found in the Atlantic Ocean​
Habitat:Shallow depths of warm, temperate ocean water 
Size:30–60 cm in bell diameter
Sting Severity:Mild
Unique Features:Numerous short, club-like appendages with mouth-arm openings for trapping prey; bioluminescent

As you’ve guessed, the appearance of Fried Egg Jellyfish resembles a fried egg with a yellowish-white bell and a brownish-red center.

These species are notable for their large size, with some individuals reaching up to 60 centimeters in diameter. The body is flat and disc-shaped, featuring a thick, gelatinous bell and long, trailing tentacles.

These jellyfish are pelagic, meaning they live in the open ocean, and are known to migrate long distances in search of food or suitable habitat.

Fried Egg Jellyfish are carnivorous, primarily feeding on plankton, small fish, crustaceans, and other jellyfish. Nevertheless, their diet varies based on location and prey availability.

They use their oral arms, lined with small, sticky tentacles, to capture and transport food to their mouth.

While they possess nematocysts or stinging cells, their sting is not considered potent and is not typically a threat to humans.

20. Cauliflower Jellyfish

Cauliflower Jellyfish
Scientific Name:Cephea cephea
Common Names:Cauliflower Jellyfish, Crown Jellyfish
Origin:Tropical waters of the western Indo-Pacific to Northern Australia, eastern Atlantic, Red Sea​
Habitat:Bays, lagoons, estuaries, pelagic zone of tropical and sub-tropical waters​
Size:Up to 60 cm in bell diameter
Sting Severity:Mild
Unique Features:Purplish-blue color, bell shape with wart-like projections; bioluminescence

The Cauliflower Jellyfish is a rare and striking marine creature. Resembling a cauliflower, these jellyfish are known for their large bell, often bluish-purple, with a warty appearance and broad circumference.

They have a transparent, jelly-like body growing up to 60 centimeters in diameter. They thrive in the deep waters of the Indo-Pacific and Atlantic regions, migrating to the surface at night from their daytime deep ocean habitat.

These jellyfish are carnivorous, feeding on plankton, shrimp, fish eggs, and larvae. They use their tentacles, covered in venomous cells called cnidocytes, to capture prey.

Although venomous, their sting is not harmful to humans. These jellyfish live in a sleep-like state at night and can form large groups known as blooms.

21. Immortal Jellyfish

Immortal Jellyfish
Scientific Name:Turritopsis dohrnii
Common Names:Immortal Jellyfish
Origin:First documented in Naples, Italy; common in Western Mediterranean and Adriatic
Habitat:Found in temperate to tropical saltwater worldwide
Size:Up to 4 mm in bell diameter
Sting Severity:Mild
Unique Features:Ability to revert from medusa to polyp stage, potentially immortal

The Immortal Jellyfish is a remarkable species found in temperate to tropical waters worldwide. These tiny jellyfish, measuring about four millimeters in diameter, have a bell-shaped medusa.

Unlike the myth about immortal lobsters, these jellyfish are truly biologically immortal.

Under stress or old age, these jellyfish can return to the polyp stage, a process known as transdifferentiation. This unique ability theoretically allows the jellyfish to bypass death.

Despite their fascinating immortality, they still face threats from diseases and predators like other jellyfish, sea anemones, and larger marine animals.

As a predatory species, Immortal Jellyfish primarily feed on zooplankton, capturing prey with their stinging tentacles.

22. Atolla Jellyfish

Atolla Jellyfish
Image credit: jelly_fish_gallery / Instagram
Scientific Name:Atolla wyvillei
Common Names:Atolla Jellyfish, Coronate Medusa, Alarm Jelly
Habitat:Deep ocean globally, especially in depths from 300 to 1,500 meters
Size:2–15 cm in bell diameter
Sting Severity:Not well documented
Unique Features:Bioluminescent; can produce flashes when attacked

The Atolla Jellyfish, also known as the Coronate Medusa, is a remarkable inhabitant of the deep sea. Characterized by a deep groove running through their bells, these jellies resemble a transparent crown.

Some Atolla species display a striking deep red color, which, intriguingly, makes them appear completely black in their preferred deep-sea habitats, ranging from 300 to 1,500 meters. This camouflage allows them to hide from predators in plain sight. 

Adding to their allure, Atolla jellyfish are bioluminescent. They emit blue light visible in the deep ocean, which may serve multiple purposes.

This bioluminescence can attract prey, startle predators, or even summon larger predators to fend off threats.

Because of this unique defense mechanism, they have earned the nickname “alarm jelly.” Atolla jellyfish feed primarily on small crustaceans, capturing them with their tentacles.

Interestingly, other Atolla species are even consumed by humans in Japan.

23. Bloody-belly Comb Jellyfish

Bloody belly Comb Jellyfish
Scientific Name:Lampocteis cruentiventer
Common Names:Bloody-belly Comb Jellyfish
Origin:North Pacific Ocean
Habitat:Midwater in the twilight (mesopelagic) zone, including the oxygen minimum zone​
Size:Up to 16 cm
Sting Severity:Does not sting
Unique Features:Known for its vibrant crimson color for camouflage in the deep sea; preys on bioluminescent organisms; uses red color to prevent its prey from illuminating its stomach​

The most striking feature of the Bloody-belly Comb Jellyfish is its vibrant, blood-red stomach, which serves a unique purpose. These jellyfish prey upon many deep-sea animals that are bioluminescent.

The jellyfish’s translucent body and red stomach help camouflage the light from its glowing prey, preventing it from being spotted. This adaptation is crucial for survival in the deep sea, where red light is almost invisible.

Bloody-belly Comb Jellyfish are also known for their shimmering, hair-like cilia, which they use to navigate through the water. They propel themselves gracefully using the rhythmic beating of these cilia.

Fun Fact: Despite being called jellyfish, Bloody-belly Comb Jellyfish are not true jellyfish. They belong to the group known as ctenophores, also called comb jellies.

24. Mushroom Cap Jellyfish

Mushroom Cap Jellyfish
Scientific Name:Rhopilema verrilli
Common Names:Mushroom Cap Jellyfish
Origin:Western Atlantic of the United States and Canada
Habitat:Estuarine, neritic zones
Size:Up to 50 cm
Sting Severity:Mild
Unique Features:Mushroom-shaped medusae; lacks tentacles but has stinging cells

The Mushroom Cap Jellyfish is a fascinating marine invertebrate belonging to the family Rhizostomatidae. These species are easily recognized by their distinctive, flat bell that resemble a mushroom cap.

Unlike many other jellyfish, they lack tentacles around the outside of their bell. Instead, they have thick oral arms that extend from the center, contributing to their remarkable structure.

Their oral arms and bells may display various colors like creamy white, light yellow, brown, blue, pink, or green, often adorned with brown or yellowish markings.

Adult Mushroom Cap Jellyfish can reach up to 50 centimeters in diameter, making them a notable presence in their natural habitat.

Despite having stinging cells called nematocysts within their bells, Mushroom Cap Jellyfish are known for their mild sting, which is often not felt by humans.

25. Red Paper Lantern Jellyfish

Red Paper Lantern Jellyfish
Image credit: moku.art / Instagram
Scientific Name:Pandea rubra
Common Names:Red Paper Lantern Jellyfish
Habitat:Deep and cold ocean waters
Size:Up to 7 cm in bell diater
Sting Severity:Not yet fully documented
Unique Features:Distinctive red subumbrella and transparent bell-shaped hood; has 14 to 30 tentacles that can extend up to 6 times its body length

The Red Paper Lantern Jellyfish is another intriguing creature of the deep sea. They’re not true jellyfish but hydrozoan, which means they belong to a different class of aquatic animals but look similar to true jellyfish.

These species stand out for their brilliant red subumbrella and transparent bell-shaped hood, giving them a unique and striking appearance. Their bells can reach a width of up to seven centimeters.

Red Paper Lantern Jellyfish thrive in environments typically inaccessible to humans. They are found primarily in the cold, deep North Pacific and North Atlantic waters and near Japan.

They are known for their lengthy tentacles, extending up to six times their body length. These tentacles help them catch prey in the vast ocean depths.

Additionally, these jellyfish serve as a floating habitat for various deep-sea creatures, including sea spiders and smaller jellyfish.

26. Crystal Jellyfish

Crystal Jellyfish
Scientific Name:Aequorea victoria
Common Names:Crystal Jellyfish
Origin:Primarily found in the Pacific Ocean
Habitat:Open waters; inshore and offshore
Size:Up to 23 cm in bell diameter
Sting Severity:Mild
Unique Features:Notable for its bioluminescence; it is transparent and colorless, with up to 150 tentacles

The Crystal Jellyfish is renowned for its bioluminescent abilities. These jellyfish thrive in nearshore and offshore waters and are known for their almost entirely transparent and colorless appearance.

What truly sets Crystal Jellyfish apart is their ability to produce a bluish light. This bioluminescent feature of these jellyfish has significantly contributed to biomedical research, especially in the study of cellular processes.

The jellyfish are relatively small, usually measuring up to 25 centimeters in diameter, and are equipped with numerous tentacles that, while containing nematocysts for capturing prey, are harmless to humans.

Frequently Asked Questions

A type of jellyfish up close

What Is the Number One Deadliest Jellyfish?

The deadliest jellyfish in the world is the Australian Box Jellyfish (Chironex fleckeri), also known as Sea Wasp.

Their tentacles are armed with nematocysts that release a potent venom, causing rapid and severe symptoms, including cardiac arrest and paralysis. Immediate medical intervention is essential when stung.

Their almost translucent appearance makes them more dangerous, as they are difficult to spot and avoid.

What Types of Jellyfish Don’t Sting?

Certain jellyfish species do not sting or have a mild sting that poses little threat to humans. Species of comb jellies do not sting. Meanwhile, Moon Jellyfish only have a mild stinging potency.

Fried Egg, Flower Hat, and Mushroom Cap Jellies are also recognized for their low toxicity and lack of danger to humans.

These non-stinging or minimally stinging jellyfish are often encountered in various marine habitats and are not considered dangerous to swimmers. Still, caution should be observed when interacting with them.

What Types of Jellyfish Are Bioluminescent?

Bioluminescent jellyfish are a captivating group in the marine world, displaying the ability to produce their own light.

Moon Jellyfish, known for their moon-like shape, are among the most popular bioluminescent jellyfish. Crystal Jellyfish are also prime examples, using unique proteins to create light.

Crown jellyfish, encompassing over 50 distinct species, such as the Atolla wyvillei, inhabit deep-sea environments and exhibit bioluminescence.

These and other bioluminescent jellyfish, such as the Red Paper Lantern and Cosmic Jellyfish, are primarily found in deep, cold ocean waters and use their bioluminescence mainly for defense against predators.

Aside from the listed jellyfish species in this guide, there are more types of jellies that are yet to be documented. So, which among the types of jellyfish species listed here is your favorite? Let us know in the comments!

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