Deadliest jellyfishes: Here are the top 10 cute ones with the most painful stings

top ten most dangerous jellyfish
Photo by Irina Iriser

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 jellyfishes and where to find them. 

In this piece, we are going to talk about 10 such jellies. 

Stay with us. This knowledge may save your life. And those of your loved ones.

Here is our list of 10 deadliest jellyfishes in the world

Let us now start talking about each of these cute yet stingy pouches.

safe sea lotion - anti jellyifhs sunscreen

1. Chironex fleckeri (sub-species of box jellyfish)

Chironex Fleckeri (sub-species of box jellyfish)

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. 
Chironex fleckeri box jellyfish sing marks on a child’s leg
Figure: Chironex fleckeri box jellyfish sing marks on a child’s leg

2. Chiropsalmus Quadrigatus

poisonous jellyfish

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:

3.Irukandji jellyfish

Irukandji jellyfish

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. 

 Irukandji jellyfish
Figure: Irukandji jellyfish swimming

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
Irukandji jellyfish
  • 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 

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. 
Sargasso seaweed
Figure: Sargasso seaweed (Image Source)
  • 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

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
Lion’s Mane jellyfish warning sign at a pear
Figure: Lion’s Mane jellyfish warning sign at a pear
  • 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 
Lion’s mane jellyfish swimming
Figure: Lion’s mane jellyfish swimming

Did you know?

6. Morbakka Fenneri

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:

7. Cannonball jellyfish

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. 
A-F shows skin condition 3 hours to 8 days after being stung by a moon jellyfish
Figure: A-F shows skin condition 3 hours to 8 days after being stung by a moon jellyfish

9. Sea nettle jellyfish

Sea nettle jellyfish
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

Purple jellyfish
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

SerialName of jellyfishLocation
1.Box jellyfishNorthern Australia and Indo-Pacific region
2.Chiropsalmus QuadrigatusPhilippines, Singapore and Australia
3.Irukandji JellyfishNorthern and southern part of Australia
4.Portuguese Man o’ WarPacific and Indian Ocean
5.Lion’s Mane JellyfishCold waters of North Pacific and the Arctic Ocean
6.Morbakka FenneriAustralia and Thailand
7.Cannonball JellyfishSouth-eastern coast of the USA as well as the mid-west Atlantic
8.Moon JellyfishWarm coastal waters
9.Sea Nettle Atlantic and the Gulf coast
10.Purple JellyfishGulf of Mexico, the North Sea, Australia and very rarely in California and Hawaii
list of all 10 deadliest jellyfishes

Some jellyfishes are deadlier than others

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. 

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. 

up to 3 pcs for the same shipping cost