Fun Blue-ringed Octopus Facts For Kids

Moumita Dutta
Oct 25, 2022 By Moumita Dutta
Originally Published on Aug 05, 2021
Edited by Monisha Kochhar
Fact-checked by Sakshi Kashyap
Blue-ringed octopus facts tell us how venomous they are
Age: 3-18
Read time: 8.3 Min

Do you like the ocean and the lives of millions of ocean animals? Well, there are many creatures in there that have the ability to kill you in minutes and you should know about them. The blue-ringed octopus species is one such animal. They are golf ball-sized octopuses that carry a toxin, that can kill tens of people within minutes. They have bright blue rings all over their body, which glow when they are about to attack. The lesser blue-ringed octopus' scientific name is Hapalochlaena maculosa and they live along the southern shore of Australia, where people have died of their bites.

The blue-ringed octopus' beak is pretty hard. It can penetrate through a wetsuit. Even though they are so dangerous to us, there are a few blue-ringed octopus' predators available, like, birds, eels, or fishes. Some of the blue-ringed octopus adaptations include an ability to camouflage, to hide from their predators.

Read on to more blue-ringed octopus facts for kids and more. If you like this article, then check out mimic octopus and shrimp facts too. 

Blue-Ringed Octopus Interesting Facts

What type of animal is a blue-ringed octopus?

The blue-ringed octopus is a kind of octopus, that belongs to the family of Octopodidae.

What class of animal does a blue-ringed octopus belong to?

The blue-ringed octopus belongs to the Cephalopoda class of animals.

How many blue-ringed octopuses are there in the world?

The exact number of blue-ringed octopuses in the world is yet unknown. Also, there isn't much information about the efforts made to conserve these octopuses, besides the fact that they are being unnecessarily killed for being poisonous.

Where does a blue-ringed octopus live?

The blue-ringed octopus lives mainly around the Philippines, Vanuatu, Indonesia, and the Solomon Islands. They can be seen in the Indo-pacific Ocean, in Australia to Japan, mainly around the tidal rock pools of the coasts.

What is a blue-ringed octopus's habitat?

The blue-ringed octopus's habitat includes shallow waters, rubble, coral reefs, or tide pools. Shallow waters basically mean about 0-65.6 ft (0-20 m) in the ocean. They are also found in muddy or sandy stretches or sometimes under rocks, where there is no abundance of algae. You can see a good amount of them after a storm has passed when they look for bivalves and crabs.

Who do blue-ringed octopuses live with?

The blue-ringed octopuses are mainly solitary in nature. They are very much possessive about their home and food. They fight with other octopuses around their homes to ward them away. They are one of the most aggressive bunch of octopuses. In other cases, animals usually don't want to fight. They either run or hide, but in the case of the blue-ringed octopus, they will fight.

How long does a blue-ringed octopus live?

These octopuses don't live for a very long time. Their average lifespan is about two years. Also, the blue-ringed octopus deaths are pretty harsh. The males of the species die shortly after mating. While the females die after only a few weeks of their partner. After the females lay eggs, they protect their eggs and in this span of time they don't eat anything. Thus, they die of starvation soon after.

How do they reproduce?

The blue-ringed octopus reproduction system is not complex at all. Once the female octopus reaches sexual maturity, she changes her color or posture in the hope of finding a mate. When the male sees this, he comes to begin their courtship. The courtship includes the males caressing the females with their arms. One of the arms of the male octopus holds the sperm, which is delivered into the oviduct of the female. Soon the female lays eggs and looks after them, as the male dies shortly after mating. The female carries the eggs under her arms and takes care of them for about 50 days. During this time, the female doesn't leave the eggs under any circumstance. They don't even eat food. So, the females also die of starvation soon after. When the eggs hatch, they join the planktons as they float to the top. At this point, these young ones are called paralarva. These young octopuses stay there for about a month and then return to the bottom again.

What is their conservation status?

According to the International Union for Conservation of Nature, the conservation status of the blue-ringed octopus is Least Concern. Their biggest threat is humans since they are killed out of fear. Also, due to global warming, they are losing their homes, which are the coral reefs.

Blue-Ringed Octopus Fun Facts

What do blue-ringed octopuses look like?

The blue-ringed octopuses are rather small-sized octopuses, compared to many other species. They are mainly dark yellow, dark brown, or yellow-tan in color. Their most distinguishable feature is the blue-colored rings they have all over their body. When these octopuses are threatened or aggravated, only then do these bright blue rings appear and can be seen glowing. They can change their color at any time because of chromatophores, which are essentially pigment cells. Like any other octopuses, they have eight arms attached to their head. On each arm, they have muscular and broad suckers. Octopuses have three hearts and one most interesting fact is their blood is transparent blue. This happens mainly because their blood holds copper, just like humans have red blood because our blood has iron. They also have a gland in their liver that holds the ink that octopuses shoot out in defense.

The blue-ringed octopus can shoot venom from their mantle

How cute are they?

As these octopuses are tiny, they might seem cute to some people. Their beautiful dark brown, dark yellow, or yellow-tan colors, along with the iridescent blue rings adds to their cuteness. However, don't get fooled by their beauty. They have enough venom in them to kill you.

How do they communicate?

These octopuses mainly communicate through their color-changing abilities. When at rest, the octopuses usually are gray or beige in color. At these times, they have brown patches or maculae all around their body. When they are threatened in some way or they are about to attack, the brown patches in their body change color and darken, while the iridescent blue rings start to glow all through their body which they use as warnings.

How big is a blue-ringed octopus?

There are around 10 different species of blue-ringed octopuses and the blue-ringed octopus size differs for all, but mostly they are very small in size. Their length is about 1.6-2.4 in (4-6 cm). Including their arms, their length reaches about 2.7-3.9 in (7-10 cm). Compared to the biggest octopus of the ocean, the Giant Pacific Octopus, whose length ranges between 9.8-16 ft (3-5 m), the blue-ringed octopus seems pretty tiny.

How fast can blue-ringed octopuses move?

The blue-ringed octopus moves in two ways. One is slower, where they crawl along whatever surface they are on. The other is jet propulsion. They draw water from their surroundings and then push it from their mantle. This helps them move pretty swiftly and quickly when in water.

How much does a blue-ringed octopus weigh?

These are pretty small octopuses. So they weigh as little as 0.9 oz (26 g).

What are their male and female names of the species?

There are no specific names for males of the species but the female of the species are called a hen.

What would you call a baby blue-ringed octopus?

Babies of the blue-ringed octopuses are called larvae.

What do they eat?

When the octopuses are young, the blue-ringed octopus diet includes only pieces of crabs. When they grow up to be adults, they start eating bivalve mollusks, live crabs, and other crustaceans. The blue-ringed octopus attack includes three methods. The first method is they inject the venom in the surrounding water of their prey. Secondly, they might inject the venom directly into their prey. Lastly, they might capture their prey into an airtight pouch made by their arms and then release the venom inside. In this way, the venom reaches the respiratory system of the prey, causes paralysis and eventually, death.

Are they dangerous?

The blue-ringed octopuses are considered one of the most poisonous aquatic animals. They are dangerous to humans, as one octopus has enough venom to kill 26 humans within minutes.

Would they make a good pet?

These octopuses are not suitable as pets. If you do get one from the market, chances are it's already been poisoned by the seller and will only live for a while. On top of that, these octopuses live only two years and only the adults are sold. Hence, they will die pretty soon after you bring them home. But most importantly, octopuses are sneaky creatures. They will always get out of the tank, however hard it is. Also, as blue-ringed octopuses are poisonous, even if they don't kill you, they might just kill your closed ones. So, a blue-ringed octopus pet should not be the best thing to think about.

Did you know...

The plural of octopus is octopuses and not octopi. The word comes from the Greek language and, mistaking it for Latin, many people started using octopi but it's the wrong term.

The Lesser or Southern blue-ringed octopus (Hapalochlaena maculosa) has smaller rings, measuring about two 0.08 in (2 mm) in diameter.

The octopus holds two different kinds of venom. One is used to kill and another for defense.

To everyone's knowledge, the species has caused three deaths by now. Two of them are in Australia and another one in Singapore.

There are no antidotes known to man that can cure the blue-ringed octopus.s bite.

Can you touch a blue-ringed octopus?

Usually, humans touch the blue-ringed octopus unknowingly. The octopus contains a venom named tetrodotoxin. Tetrodotoxin has the ability to paralyze its prey. If you do touch one and get bitten, look for the blue-ringed octopus bite mark and get it treated immediately, or else your entire body may paralyze and respiratory systems may start to fail and result in death. If you do manage to get the treatment as quickly as possible, you can survive and this has actually happened.

How poisonous is a blue-ringed octopus?

Not only is the blue-ringed octopus the most poisonous animal in the ocean, but also it is more poisonous than all the land mammals. The blue-ringed octopus bite holds the punch to be able to kill 26 humans. The blue-ringed octopus venom is 1000 times stronger than cyanide. It gets created by bacteria in the salivary glands of the octopuses.  

Here at Kidadl, we have carefully created lots of interesting family-friendly animal facts for everyone to discover! Learn more about some other arthropods including sea squirt, or sea snake.

You can even occupy yourself at home by drawing one on our blue-ringed octopus coloring pages.

Blue-ringed octopus Facts

What Did They Prey On?

Crabs, mollusks, other crustaceans

What Type of Animal were they?


Average Litter Size?

Approximately 100

How Much Did They Weigh?

0.9 oz (26 g)

What habitat Do they Live In?

shallow waters, tide pools, coral reefs

Where Do They Live?

Indo-Pacific Ocean, philippines, indonesia, solomon islands, vanuatu, australia

How Long Were They?

2.7-3.9 in (7-10 cm) (including arms)

How Tall Were They?








Scientific Name

Greater blue-ringed octopus - Hapalochlaena lunulata Lesser blue-ringed octopus - Hapalochlaena maculosa

What Do They Look Like?

Dark brown, yellow-tan, dark yellow

Skin Type

Soft mantle

What Are Their Main Threats?


What is their Conservation Status?

Least Concern
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Written by Moumita Dutta

Bachelor of Arts specializing in Journalism and Mass Communication, Postgraduate Diploma in Sports Management

Moumita Dutta picture

Moumita DuttaBachelor of Arts specializing in Journalism and Mass Communication, Postgraduate Diploma in Sports Management

A content writer and editor with a passion for sports, Moumita has honed her skills in producing compelling match reports and stories about sporting heroes. She holds a degree in Journalism and Mass Communication from the Indian Institute of Social Welfare and Business Management, Calcutta University, alongside a postgraduate diploma in Sports Management.

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