“The octopus is arguably the smartest invertebrate on earth — watching one on the reef, changing colour and shape in real time, is an encounter you don’t forget.”
Octopus of the Great Barrier Reef – Master of Disguise and Intelligent Predator
Octopus of the Great Barrier Reef: The Ultimate Guide
Taxonomy
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Order: Octopoda
Family: Octopodidae (most reef species, including the day octopus and blue-ringed octopuses)
Related Categories:
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- Great Barrier Reef Animals
- Cephalopods
- Marine Life
- Reef Creatures
- Snorkelling and Diving Encounters
Meet the Amazing Octopus of the Great Barrier Reef
The octopus is one of the most intelligent and fascinating creatures found on the Great Barrier Reef. With eight powerful arms, remarkable problem-solving abilities, and the ability to instantly change colour and texture, they are true masters of disguise.
Watch an Octopus in Action
Octopuses are among the most intelligent animals on the Great Barrier Reef. Watch how they change colour, camouflage themselves, and move through coral reef habitats.
While they are not as commonly seen as clownfish or sea turtles, encountering an octopus while snorkelling or diving is often a highlight of any reef adventure. These curious animals can be found hiding among coral bommies, rocky crevices, sandy seabeds, and seagrass meadows throughout the Great Barrier Reef.
Octopuses are cephalopods, a class of molluscs that also includes squid, cuttlefish and nautiluses. They are known for their intelligence, adaptability, and unique behaviours that continue to amaze marine biologists around the world.
Quick Facts About Great Barrier Reef Octopus
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- Octopuses have three hearts and blue blood.
- They can instantly change colour, pattern, and skin texture.
- All octopuses have eight arms lined with suckers.
- They are highly intelligent and capable of solving complex problems.
- They have no bones, allowing them to squeeze through tiny spaces.
- They are skilled hunters that feed on crabs, shellfish, and small fish.
- Several species can be found throughout the Great Barrier Reef.
Species Found on the Great Barrier Reef
The most commonly encountered species include
Day Octopus (Octopus cyanea)
The Day Octopus is one of the reef’s most impressive cephalopods. Active during daylight hours, it can rapidly change colours while hunting across coral reefs and sandy lagoons.
Other Reef Octopuses
The day octopus is also called the reef octopus, but several other octopus species live on the reef too. Often found hiding among coral formations and rocky ledges, they are masters of camouflage and can disappear into their surroundings within seconds.
Blue-Ringed Octopus
Although small and rarely seen, the Blue-Ringed Octopus is famous for its bright blue warning rings. It possesses a powerful venom and should never be touched or disturbed. The venom contains tetrodotoxin, and the bite is often painless. Warning signs include numbness around the mouth, face and neck and difficulty breathing. Healthdirect first aid advice: call 000, keep the person calm and still, apply a pressure immobilisation bandage if the bite is on a limb, and start CPR if needed. Never pick up an octopus, or a shell one may be hiding in.
Mimic Octopus
The mimic octopus (Thaumoctopus mimicus) can imitate the shapes and movements of other animals. It was first recorded in Australian waters off Lizard Island in 2012 and is very rarely seen. Its relative the coconut (veined) octopus, filmed in Indonesia carrying coconut shells to use as shelters, gave one of the first recorded examples of tool use by an invertebrate.
Incredible Camouflage Abilities
One of the octopus’s most remarkable abilities is camouflage.
Specialised skin cells called chromatophores allow the octopus to instantly alter its colour. Additional skin structures help it change texture, making it resemble coral, rocks, algae, or sand.
This extraordinary adaptation helps octopuses avoid predators and ambush prey. Divers often swim past an octopus without ever realising it is there.
How Intelligent Are Octopuses?
Octopuses are considered among the most intelligent invertebrates on Earth.
Researchers have documented octopuses:
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- Solving puzzles.
- Opening jars.
- Escaping enclosures.
- Recognising patterns.
- Learning through observation.
- Using tools for protection.
Their complex nervous systems and problem-solving abilities continue to fascinate scientists studying marine life on the Great Barrier Reef.
What Do they Eat?
Octopuses are carnivorous hunters.
Their diet commonly includes:
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- Crabs
- Shrimp
- Prawns
- Molluscs
- Small fish
- Shellfish
Using powerful suction cups and a sharp beak hidden beneath their arms, octopuses can capture and consume a wide variety of prey.
Where Can You See Octopus on the Great Barrier Reef?
Although they are experts at hiding, octopuses can be found across many reef locations including:
The best opportunities often occur during scuba dives, guided snorkelling tours, and night dives when many species become more active.
See them on a reef tour
Octopus can be spotted on outer reef snorkel and dive trips, though they are masters of hiding and sightings are never guaranteed.
Threats to Octopus Populations
Octopus populations face several challenges including:
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- Habitat degradation
- Coral reef damage
- Ocean pollution
- Marine debris
- Climate change
- Rising ocean temperatures
Healthy reef ecosystems are essential for supporting octopus populations and the many marine species that depend upon coral reef habitats.
Why they Are Important to the Reef Ecosystem
Octopuses play an important role in maintaining ecological balance.
As predators, they feed on crabs, shellfish and small fish. They also provide food for larger marine animals including reef sharks, moray eels, dolphins, and large fish species.
Octopuses need plenty of crabs, shellfish and places to shelter, so they do best on reefs with a rich supply of both.
7 Reasons Divers Love Seeing Octopus
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- Their camouflage abilities are truly incredible
- Every encounter feels unique and unpredictable.
- They display fascinating intelligence.
- They often interact with curious divers.
- Their colour-changing displays are spectacular.
- They are among the reef’s most skilled hunters.
- Spotting one feels like discovering a hidden treasure.
Common Names
Octopus, day octopus (also called big blue octopus or reef octopus), blue-ringed octopus, mimic octopus.
Identification Notes
All octopuses have eight arms lined with suckers, no shell and a hard beak at the centre of the arms. About two-thirds of an octopus’s nerve cells are in its arms. The day octopus (Octopus cyanea) can grow to about 6 kg and is often seen hunting on reef flats around dawn and dusk.
Learning about reef animals in class? We help schools, universities and study groups plan educational trips to the Great Barrier Reef. Depending on the program, groups can enjoy guided snorkelling and marine biology presentations.
Great Barrier Reef Educational Groups →
Frequently Asked Questions
Are octopuses dangerous?
Can octopuses change colour?
How many hearts does an octopus have?
Where is the best place to see an octopus on the Great Barrier Reef?
How long do octopuses live?
Discover More Great Barrier Reef Animals
An encounter with an octopus is one of the most memorable wildlife experiences on the Great Barrier Reef. Their intelligence, camouflage abilities, and fascinating behaviours make them one of the reef’s most remarkable creatures. Whether you’re snorkelling over colourful coral gardens or exploring deeper dive sites, keep your eyes peeled, you never know when an octopus may reveal itself from its perfectly hidden home.
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