A black and teal-green articulated 3D-printed flexi octopus on a light wooden desk, its eight segmented arms spread out in a star, against a calm blue wall with a plain notebook at the edge.

Cool Octopus Facts for Kids: 3 Hearts, Blue Blood, 8 Arms

5 min read Updated October 4, 2026 By Kahaus · printed in Poland

In short

An octopus has eight arms, three hearts and blue blood, and there is not a single bone in its body.
It changes colour in a blink, squirts ink to escape and is one of the cleverest animals without a backbone.
Our 17 cm flexi octopus moves all eight arms independently. Like all our figures, it is not for children under 3.

Octopus facts are the kind children repeat at dinner for a week: three hearts, blue blood, arms that can taste. They sound made up, but they are true, and a few are even stranger than they sound.

We print a flexi octopus on our own printers in Poland, so octopus questions from children and parents reach us all the time. Below: what kind of animal it is, a short fact sheet, eight cool octopus facts (one for every arm), how clever it really is and a small game with figures.

What kind of animal is an octopus?

An octopus is not a fish. It is a mollusc, which makes it a distant relative of snails, mussels and clams. Together with squid and cuttlefish it belongs to the cephalopods, a Greek name that roughly means "head-foot": the arms grow straight from the head.

Octopuses live in seas and oceans all over the world, from warm shallow reefs to cold deep water. Most of them live alone. They hide in cracks and holes between rocks and come out to hunt crabs, shrimps and shellfish.

Octopus fact sheet

Question	Answer
What animal is it?	A mollusc from the cephalopod group, related to squid and cuttlefish
Where does it live?	In seas and oceans all over the world
Arms	Eight, covered in suckers
Hearts	Three
Blood	Blue
Bones	None, only a hard beak
How it defends itself	Changes colour, squirts ink, hides in small gaps
What it eats	Mainly crabs, shrimps and shellfish

8 cool octopus facts, one for every arm

They are arms, not tentacles. Scientists call the eight limbs of an octopus arms. Tentacles are the two longer hunting limbs of squid and cuttlefish. In everyday language people use both words, and our own product page says tentacles too.
The suckers can taste. An octopus feels and tastes with its suckers. When it touches a rock, it also finds out whether something tasty is hiding underneath.
Three hearts. Two small hearts pump blood through the gills, and the third one sends it around the rest of the body.
Blue blood. Our blood is red because it carries oxygen with the help of iron. Octopus blood uses copper instead, and that makes it blue.
Colour change in a blink. The skin is full of tiny colour cells that the octopus can open and close. It can match the rocks around it, make its skin look bumpy like seaweed, or flash colours when it is upset.
An ink cloud as an escape trick. When a predator comes too close, the octopus squirts a dark cloud of ink into the water and swims off while the attacker is still confused.
No bones at all. The only hard part of its body is the beak in the middle, where the arms meet. That is why an octopus can squeeze through a gap that looks far too small for it.
Jet swimming. An octopus usually crawls on its arms. When it is in a hurry, it pushes water out through a tube called a siphon and shoots backwards like a small rocket.

Blue-green 3D printed flexi octopus, 17 cm, with eight segmented arms spread out — Our flexi octopus, 17 cm, in blue-green. Each of the eight arms moves on its own. See the product →

How clever is an octopus?

Very clever, for an animal without a backbone. In aquariums and laboratories, octopuses have learned to unscrew jars to reach the food inside, to find their way through simple mazes and to tell apart the people who look after them.

Here is something even stranger: a large part of an octopus's nerve cells sits in its arms, not in its head. Each arm can feel, grab and react partly on its own, while the brain decides where the whole animal goes. Scientists are still working out exactly how this works, which makes the octopus a favourite for children who like big questions.

Eight arms or eight legs? A game with flexi figures

A good follow-up to octopus facts is a small comparison game. Put an octopus next to a spider and ask: who has eight arms and who has eight legs? Then add a chameleon, another animal known for changing colour, and a dolphin, which lives in the sea but is not a fish either.

Figure	Size	What it shares with an octopus
Flexi octopus	about 17 cm	Eight arms, each one moves on its own
Articulated tarantula	20 cm leg span	Also eight limbs, but they are legs on a spider
Flexi scorpion	13.9 cm	Eight legs too, plus two pincers and a curling tail
Flexi chameleon	about 17 cm	Changes colour in nature, but it is a lizard on land
Mini animal, Dolphin variant	6 cm	Lives in the sea, but it is a mammal

The octopus is printed in one piece with the joints built in (print-in-place), so there is nothing to glue or assemble. It sits comfortably in one hand, it is quiet and it comes in four colourways: blue-green, blue-green-violet, red-gold and red-yellow-green. For a younger child who loves the sea, the 6 cm mini animal in the Dolphin Blue Silk variant is the smaller choice; the same family also has a narwhal and a manatee.

Flexi chameleon, 17 cm, 3D printed in a shimmering red-yellow-green finish, resting on a hand — Flexi chameleon, 17 cm: the tail curls and uncurls. See the product →

Articulated 3D printed tarantula with a 20 cm leg span and eight jointed legs, on an open hand — Tarantula, 20 cm leg span: eight legs to count. See the product →

More moving animals are in Flexi Animals and in our guide to articulated 3D printed animals and which of them really move. If the octopus is meant as a present, Gift Ideas has more ideas, and older children who mostly want something for their hands will find it in Fidget Toys.

Safety: our figures have small moving parts and are not suitable for children under 3. The octopus product page gives no age marking, so with younger children, play together.

See all flexi animals

Questions about octopuses

Is an octopus a fish?

No. It is a mollusc, related to snails, mussels, squid and cuttlefish. It has no fins and no bones.

Why is octopus blood blue?

Because it carries oxygen with the help of copper. Our blood uses iron for the same job, and that makes it red.

Is the flexi octopus suitable for a young child?

The product page gives no age marking. Our figures have small moving parts, so they are not for children under 3, and with preschoolers it is best to play together.