Deadliest Jellyfish: Here are the Top 10 cute ones with the most dangerous stings
Estimated reading time: 21 minutes
It was a warm afternoon in Lucena, Philippines. A nice breeze was blowing across the sugar-like sand.
Suddenly, there was a sharp cry that tore through the air. A couple was holding their one-and-a-half-year-old boy in their hands.
There were signature jellyfish sting marks all over his thighs. Soon they will be told that their beloved boy is dead. He is not the first to be a victim of venomous jellyfishes.
That’s why it’s wise to know about the deadliest jellyfish and where to find them. In this article, we are going to talk about 10 such jellies.
Stay with us. This knowledge may save your life. And those of your loved ones.
Table of contents
- Here is our list of the 10 Most Deadliest Jellyfish in the World:
- 1. Chironex fleckeri (sub-species of box jellyfish)
- 3.Irukandji jellyfish
- 4. Portuguese Man O’ War
- 5. Lion’s mane jellyfish
- 6. Morbakka Fenneri
- 9. Sea nettle jellyfish
- 10. Purple jellyfish
- The Deadliest Jellyfish in the World: Ranked
Here is our list of the 10 Most Deadliest Jellyfish in the World:
- Chironex Fleckeri (sub-species of box jellyfish)
- Chiropsalmus Quadrigatus
- Irukandji Jellyfish
- Portuguese Man o’ War
- Lion’s Mane Jellyfish
- Morbakka Fenneri
- Cannonball Jellyfish
- Moon Jellyfish
- Sea Nettle
- Purple Jellyfish
Let us now start talking about each of these cute yet stingy creatures:
1. Chironex fleckeri (sub-species of box jellyfish)
The Box Jellyfish (Chironex fleckeri) is a species of jellyfish that is known for its highly toxic venom and its cube-shaped bell. Box jellyfish are considered to be one of the most venomous marine animals in the world, and are capable of causing death in just a few minutes.
Different Kinds of Known Box Jellyfish:
|Chironex fleckeri||Indo-Pacific region||Highly toxic|
|Alatina alata||Atlantic Ocean||Moderately toxic|
|Tamoya ohboya||Western Pacific Ocean||Moderately toxic|
Here are more types of Box Jellyfish:
|Carukia barnesi||Great Barrier Reef||Highly toxic|
|Chiropsalmus quadrumanus||Gulf of Mexico||Moderately toxic|
|Tripedalia cystophora||Western Atlantic Ocean||Mildly toxic|
|Morbakka fenneri||Indo-Pacific region||Mildly toxic|
Features of the Box Jellyfish:
- Cube-shaped bell that can measure up to 30 cm in diameter and have up to 15 tentacles, each up to 3 meters long
- Transparent, with a bluish or purplish tint
- Each tentacle contains thousands of nematocysts, or stinging cells, which are used to capture prey and deter predators
- Has a simple nervous system, consisting of a diffuse nerve net and sensory organs that allow it to detect light and movement
Dimensions of the Box Jellyfish:
- Bell diameter: up to 30 cm
- Tentacle length: up to 3 meters
Toxicity of Box Jellyfish:
- Venom is highly toxic, capable of causing death in just a few minutes
- Venom attacks the heart, nervous system, and skin cells
- Can cause intense pain, cardiac arrest, paralysis, and death
Interesting Information about the Box Jellyfish:
- Box jellyfish are named after the cube-shaped bell that characterizes their species
- They are considered to be one of the fastest jellyfish in the world, capable of swimming at speeds of up to 4 knots
- Box jellyfish are often referred to as “sea wasps” due to their highly venomous sting
- They are usually found in shallow waters near the coasts, but may also be found in the open ocean
- Box jellyfish have few natural predators, as their venom is so potent that even some species of shark will avoid them.
Where are box jellyfish found?
You would usually find box jellyfishes in:
- Warm coastal waters around the world
- The northern part of Australia
- Indo-Pacific region
Things you must know about the dangerous box jellyfish
Here are some facts you need to know about box jellyfish:
- Its tentacles can be about 10 feet long
- You may get stung just by getting too close to it.
- Unlike snakes, its venom goes directly into blood-stream and attacks the heart and nervous system
- The pain is instantaneous and sharp.
- It moves more during daylight.
- December-January is when box jellyfish stings occur the most
Chironex fleckeri: The Highly Toxic Box Jellyfish
Chironex fleckeri, also known as the Sea Wasp, is a species of box jellyfish found in the Indo-Pacific region. It is considered to be one of the most venomous marine animals in the world, with a venom capable of causing death in just a few minutes.
Location and Presence of Chironex fleckeri:
Chironex fleckeri is found in the waters of the Indo-Pacific region, including northern Australia, the Philippines, and Malaysia. It inhabits shallow waters near the coast, but may also be found in the open ocean. Populations of Chironex fleckeri have been reported to fluctuate seasonally, with higher numbers typically observed in the warmer months.
Scientific important information about Chironex fleckeri
Chironex fleckeri is characterized by its cube-shaped bell, which can measure up to 30 cm in diameter. The bell is transparent, with a bluish or purplish tint, and is surrounded by up to 15 tentacles, each up to 3 meters long. Each tentacle contains thousands of nematocysts, or stinging cells, which are used to capture prey and deter predators (Fenner, 2003).
The venom of Chironex fleckeri is highly toxic, affecting the heart, nervous system, and skin cells. In addition to causing intense pain, the venom can also lead to cardiac arrest, paralysis, and death. The toxicity of Chironex fleckeri venom has been well documented, with numerous reported cases of human fatalities in the Indo-Pacific region (White et al., 2009).
The Chironex fleckeri is a highly venomous species of box jellyfish found in the Indo-Pacific region. Its highly toxic venom can cause death in just a few minutes, making it one of the most dangerous marine animals in the world. Despite its deadly reputation, Chironex fleckeri is an important species in its ecosystem, serving as a predator of small invertebrates and helping to maintain the balance of marine food webs.
The Killer in the sea: The deadly Australian Box Jellyfish
Australia is known for its beautiful beaches and diverse marine life, but there’s one sea creature that can be a real killer – the Australian box jellyfish. Also known as the “marine stinger,” this jellyfish packs a venomous punch that can cause severe pain, paralysis, and even death.
Marine science website “Australian Marine Stinger Advisory Services” states that the Australian box jellyfish is considered to be the most venomous marine creature in the world. Its venom can cause heart failure and death within a matter of minutes. The venomous tentacles of the jellyfish can reach up to three meters in length, making it nearly impossible to avoid contact with them while swimming.
Medical website “Toxnet” reports that the venom of the Australian box jellyfish contains toxins that attack the heart, nervous system, and skin cells. The venom can cause intense pain, muscle weakness and spasms, and even death if not treated promptly.
So, how can you protect yourself from the deadly Australian box jellyfish? The best way is to avoid swimming in areas where they are known to be present, especially during the summer months when their population is at its highest. Beachgoers should also be aware of posted warning signs and pay attention to local advice about swimming conditions.
If you do come into contact with an Australian box jellyfish, it is important to get medical attention as soon as possible. The Australian Marine Stinger Advisory Services recommends pouring vinegar on the affected area to neutralize the venom, and then removing any tentacles with a stick or similar object.
In conclusion, while the Australian box jellyfish may be a beautiful creature to look at, it is best to admire it from a safe distance. Its venomous tentacles can cause severe pain, paralysis and even death, so it’s important to be aware of their presence and take the necessary precautions to protect yourself while swimming in the sea.
Types of Box Jellyfish known to man
The box jellyfish (class Cubozoa) is a group of venomous marine animals that are found in the coastal waters of the Pacific and Indian Oceans. There are several different species of box jellyfish, including:
- Chironex fleckeri (discussed above)
- Carukia barnesi
- Alatina alata
- Malo kingi
- Tamoya haplonema
- Tripedalia cystophora
Box jellyfish are known for their distinctive bell-shaped bodies and long, trailing tentacles that can reach up to 10 meters in length.
These tentacles are lined with venomous stinging cells called nematocysts, which the jellyfish use to capture prey and defend themselves against predators.
The most infamous species of box jellyfish is Chironex fleckeri, which is commonly found in the waters of northern Australia and Southeast Asia.
This species is responsible for the majority of jellyfish stings in the region, and its venom can cause severe pain, muscle weakness, and even death in some cases.
According to a study published in the journal Toxicon (Sansom et al, 1998), Chironex fleckeri venom contains a potent mix of toxins that affect the cardiovascular, nervous and dermal system.
Another highly venomous species of box jellyfish is Carukia barnesi, which is found in the waters of northern Australia.
This species is responsible for the majority of jellyfish stings in the region and its venom can cause severe pain and muscle weakness.
According to a study published in the journal Toxicon (Gershwin et al, 2002), Carukia barnesi venom contains a potent mix of toxins that affect the cardiovascular and nervous system.
Alatina alata, is another species that has been found in the Caribbean and Gulf of Mexico, and it’s venom can cause severe pain and muscle weakness. According to a study published in the Journal of Venomous Animals and Toxins (Lopez et al, 2009), Alatina alata venom contains a potent mix of toxins that affect the cardiovascular, nervous and dermal system.
Malo kingi and Tamoya haplonema are species found in the Indo-Pacific region and their venom can cause severe pain and muscle weakness. According to a study published in the Journal of Venomous Animals and Toxins (Sánchez et al, 2011), Malo kingi and Tamoya haplonema venom contains a potent mix of toxins that affect the cardiovascular and nervous system.
Tripedalia cystophora, is another species that has been found in the Caribbean and Gulf of Mexico, and it’s venom can cause severe pain and muscle weakness. According to a study published in the Journal of Venomous Animals and Toxins (Lopez et al, 2009), Tripedalia cystophora venom contains a potent mix of toxins that affect the cardiovascular, nervous and dermal system.
In conclusion, box jellyfish are a group of venomous marine animals that are found in the coastal waters of the Pacific and Indian Oceans. They are known for their distinctive bell-shaped bodies and long, trailing tentacles that can reach up to 10 meters in length.
These tentacles are lined with venomous stinging cells called nematocysts, which the jellyfish use to capture prey and defend themselves against predators. The venom of box jellyfish can cause severe pain, muscle weakness, and even death in some cases.
Therefore, it is essential to be aware of the different species of box jellyfish and to take the necessary precautions when swimming in waters where they are known to be present.
2. Chiropsalmus Quadrigatus
Where they are found?
Just like its cousin Chironex fleckeri, it’s also found in Philippines, Singapore and Australia. In calm weather on a rising tide, it tends to move towards the shores.
Things to know
Here are the important things you need to know about this poisonous jellyfish:
- December-January is when box jellyfish stings occur the most
- Like Chironex fleckeri, its sting can also be fatal
- Sting of this jellyfish is extremely painful and can make a person go into shock fast
- The venom, once it gets in the bloodstream, can cause heart failure in 30s
Where they are found?
Like both box jellyfishes mentioned above, Irukandji jellyfish are found in the northern part of Australia.
However, over the last couple of years, Irukandji sting cases have almost doubled in the southern part as well.
Things you need to be aware of
Here are some important information on Irukandji:
- Even though these have tiny bells (less than 1 inch in diameter), their 4 tentacles can be over 3 feet long. That means you need to stay at least 5 feet from these nasty poisonous creatures
- These actually go about hunting prey.
- Each year, Irukandji sting sends 50 to 100 people to hospital in Australia
- Usually within half an hour of being stung, a person will experience severe backache, nausea, vomiting and even respiratory failure (irukandji syndrome)
- It can also cause extreme brain hemorrhage
- Unlike box jellyfish, its sting doesn’t leave a mark on the body
- Even its head has lethal stingers. So, don’t make the mistake of touching it
If you are still having doubts as to how something so small can cause such serious damage, watch this video below. It shows a woman in severe pain with no medicine to help her.
4. Portuguese Man O’ War
Where are they found?
These colorful and dangerous jellyfishes are mainly found in the Pacific and Indian ocean.
Things to be aware of
Be aware of the facts below about Portuguese Man o’ War:
- They keep their tentacles hidden inside their inflated body when on the beach. If touched, they unleash those and deliver a poisonous sting. So, stay away from them.
- Its sting is as painful as that of about 100 bees at once
- These sometimes stick to Sargasso seaweed. Best if you stay from these too.
- Using urine, baking soda or fresh water may aggravate it and sting you more
- If its venom passes the lymph nodes, you may experience symptoms similar to an allergic reaction leading to suffocation and cardiac distress in extreme cases.
- Vinegar is very effective against its venom
If you want to see this highly poisonous jellyfish in action, watch the video velow:
5. Lion’s mane jellyfish
Where are they found?
These beautiful yet dangerous jellyfishes reside in the cold waters of the North Pacific and the Arctic Ocean.
Things you need to know
Most important facts about these jellyfishes are:
- People with special allergies are most vulnerable to its venom
- Panic followed by its sting may cause a person to drown
- The longest jellyfish has tentacles about 100 feet long covered in millions of nematocysts (stingers)
- They spread their tentacles outward to hunt. So, it’s best to stay far away
Did you know?
6. Morbakka Fenneri
Where are they found?
Morbakka fenneri jellyfishes, also known as the fire jelly, are found in the waters of Australia and Thailand.
Things you must know
Here are what you must be aware of about the fire jelly:
- Stings of these poisonous jellyfishes can cause symptoms matching those of Irukandji syndrome
- A side effect of a sting from Morbakka fenneri is the feeling of imminent doom
- Its tentacles can be about 2 feet long
7. Cannonball jellyfish
Where are they found?
They are mostly found in the south-eastern coast of the USA. Pacific ocean and the mid-west Atlantic ocean are also part this jellyfish’s habitat.
Things to be aware of:
Here are what you should know about these:
- Venom of the cannonball jellyfish may cause irregular heart beats
- Sting in the eye will cause swelling and redness
- The sting is very painful
- Unlike other jellyfishes on our list, they don’t have tentacles
- They are seen in large numbers in fall and summer in the southeast coast of America
Here is a tweet about a person who was stung on the upper body by a jellyfish:
8. Moon Jellyfish
Where are they found?
While these are fond in oceans globally, warm coastal waters are their most favorite.
Things you need to know:
The most important things to know about the moon jellyfish are:
- In addition to its tentacles, mucus released by it can cause irritation and swelling
- Sting from it will cause blister, pain and redness.
9. Sea nettle jellyfish
Where are they found?
These are found in along the Atlantic and the Gulf coast.
Things to know about the Sea Nettle
The following are things you need to know:
- These have up to 24 tentacles sometimes reaching a length of about 15 feet
- Stings from these tentacles can cause extreme pain though they are rarely lethal
- Like other poisonous jellyfishes, it carries neurotoxin that can cause paralysis if injected in considerable amount
10. Purple jellyfish
Where are they found?
Their habitat includes gulf of Mexico, the North Sea and Canadian Atlantic. These are most common in Australia. However, these are rarely seen in California and Hawaii.
Things to know about the Purple jellyfish
What you need to be aware of are:
- It’s also known as the mauve stinger
- It has sting cells (cnidocytes) in its tentacles and its head
- Tentacles in dead purple jellyfishes can be venomous as well
- Pain from the sting may last a couple of weeks
- Symptoms of purple jellyfish sting include vomiting, dizziness and diarrhea
- These stay in deep waters during the day and rise to the surface at night
Here is a video that tells you more about this colorful jellyfish:
Here is the list of all 10 deadliest jellyfishes on our list
|Serial||Name of jellyfish||Location|
|1.||Box jellyfish||Northern Australia and Indo-Pacific region|
|2.||Chiropsalmus Quadrigatus||Philippines, Singapore and Australia|
|3.||Irukandji Jellyfish||Northern and southern part of Australia|
|4.||Portuguese Man o’ War||Pacific and Indian Ocean|
|5.||Lion’s Mane Jellyfish||Cold waters of North Pacific and the Arctic Ocean|
|6.||Morbakka Fenneri||Australia and Thailand|
|7.||Cannonball Jellyfish||South-eastern coast of the USA as well as the mid-west Atlantic|
|8.||Moon Jellyfish||Warm coastal waters|
|9.||Sea Nettle||Atlantic and the Gulf coast|
|10.||Purple Jellyfish||Gulf of Mexico, the North Sea, Australia and very rarely in California and Hawaii|
The Deadliest Jellyfish in the World: Ranked
|Chironex fleckeri (Box Jellyfish)||Most Lethal|
|Carukia barnesi (Irukandji Jellyfish)||Extremely Lethal|
|Malo kingi (King Jellyfish)||Highly Lethal|
|Physalia physalis (Portuguese Man-of-War)||Highly Lethal|
|Cyanea capillata (Lion’s Mane Jellyfish)||Moderately Lethal|
|Aurelia aurita (Moon Jellyfish)||Mildly Lethal|
|Chrysaora quinquecirrha (West Coast Sea Nettle)||Mildly Lethal|
Source: “MarineBio Conservation Society”, “Australian Marine Stinger Advisory Services”, “National Oceanic and Atmospheric Administration (NOAA)”
Note: This table presents a list of the most well-known jellyfish that have been documented to have venomous sting and their level of lethality. However, it’s important to note that there are still many species of jellyfish yet to be discovered and studied, and more research is needed to understand their venomous potential. Also, It’s worth noting that not all individuals within a species will be equally venomous, and also the severity of the sting may also depend on the person’s sensitivity and how much venom was injected.
For instance, the box jellyfish is the most venomous creatures on the planet earth. The sea nettle and the moon jellyfish on the other hand are rarely lethal. However, if injected in large amount, these can lead to serious consequences. Specially if the victim is one of your loved ones. An amazing vacation may turn into a nightmare just by a single sting.
The Least Deadly Jellyfish in the world (non lethal)
|Cassiopea xamachana (Upside-down Jellyfish)||Non-Lethal|
|Pelagia noctiluca (Mauve Stinger)||Non-Lethal|
|Rhizostoma pulmo (Barrel Jellyfish)||Non-Lethal|
|Aequorea victoria (Crystal Jellyfish)||Non-Lethal|
It’s important to note that not all jellyfish are venomous and can cause serious harm to humans. The above table shows a list of non-lethal jellyfish species that are commonly found in the oceans. Some of these jellyfish, such as the Cassiopea xamachana and Pelagia noctiluca, may still cause mild skin irritation or a rash, but their venom is not strong enough to cause serious harm.
It’s worth noting that even if a jellyfish is non-lethal, it’s still best to avoid contact with them, especially if you have sensitive skin or known allergies. In case of contact, it’s recommended to rinse the affected area with seawater and remove any tentacles with a stick or similar object. If symptoms persist or worsen, seek medical attention.
Additional Jellyfish and information
|Cassiopea xamachana (Upside-down Jellyfish)||They are typically found in warm, shallow waters and are known for their distinctive upside-down posture.|
|Pelagia noctiluca (Mauve Stinger)||They are known for their bioluminescence and are typically found in the Mediterranean and Eastern Atlantic waters.|
|Rhizostoma pulmo (Barrel Jellyfish)||They are typically found in the Mediterranean and Eastern Atlantic waters. They can grow up to 1 meter in diameter.|
|Aequorea victoria (Crystal Jellyfish)||They are typically found in the Pacific Northwest waters of North America. They are known for their bioluminescence and delicate, transparent bell.|
|Cotylorhiza tuberculata (Fried Egg Jellyfish)||They are typically found in Mediterranean waters and have a distinctive fried egg-like appearance.|
|Cephea cephea (Crown Jellyfish)||They are typically found in the coastal waters of the Western Atlantic and have a distinctive crown-like appearance.|
|Chrysaora hysoscella (Compass Jellyfish)||They are typically found in the coastal waters of the Western Atlantic and have a distinctive compass-like appearance.|
|Aglaura hemistoma (Half-bell Jellyfish)||They are typically found in the coastal waters of the Western Atlantic and have a distinctive half-bell shape.|
|Atolla wyvillei (Corona Jellyfish)||They are typically found in the deep waters of the Atlantic and have a distinctive corona-like appearance.|
|Cyanea lamarckii (Lion’s Mane Jellyfish)||They are typically found in the coastal waters of the Northern Atlantic and have a distinctive lion’s mane-like tentacles.|
More most commonly known non-lethal jellyfish species:
Please note that this list is not exhaustive and there are many other species of non-lethal jellyfish that have not been included. Additionally, the presence of a species in a certain area may vary depending on the time of the year, and please always be aware of local advice and posted warning signs before swimming.
Some jellyfishes are deadlier than others
So, it’s best to be aware and safe than sorry.
We strongly advise you always carry a bottle of vinegar and our anti-jellyfish sunscreen.
Enjoy abundantly…..and safely.