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Aquarium of the Pacific - Online Learning Center - Species Print Sheet

Conservation Status:  Data deficient

Climate Change:  Vulnerable

Aquatic SpeciesDay Octopus

Octopus cyanea Cephalopods

Day Octopus on Blue Background Day octopus in the Tentacles and Ink exhibit | Brian Gray/Aquarium of the Pacific
Day Octopus on Blue Background - popup
Day octopus in the Tentacles and Ink exhibit Brian Gray/Aquarium of the Pacific

Species In-Depth | Print full entry

Geographic Distribution

This species is found in the Indo-Pacific Ocean, from the Eastern coast of Africa to Hawaiian Islands, in Pacific and Indian Oceans.


Day octopuses are found in lairs or dens in coral reefs or excavated in sand or coral rubble.

Physical Characteristics

This octopus is typically brown to reddish brown in color with dark blue circles. Chromatophores in their skin allow it to change both color and skin texture. It has eight arms lined with suckers on one side. These suckers are rimmed with millions of texture receptors and thousands of chemical receptors. A sac-like body known as a mantle contains their gills, siphon, and internal organs. It has raised eyes with excellent eyesight. Their mouth is located on the underside of their body. They have a well-developed nervous system and three hearts; one pumps blood throughout its body and the other two hearts pump blood to the gills.


The mantle size can be up to 6.3 inches (16 centimeters) in length; the arms are typically 31.5 inches (80 centimeters) long.


Unlike most octopuses that are nocturnal hunters, the day octopus hunts during the day. It is most active at dawn and dusk. Opportunistic feeders, they eat small fish, crustaceans, and molluscs. They primarily use their tentacles to locate prey. This octopus may pounce on its prey, enveloping it with its arms and body webbing or hold it with its tentacles, injecting a toxin produced by its salivary glands, paralyzing the prey and starting the digestive process. It typically returns to its lair to eat.


Both sexes become sexually mature at approximately ten to twelve months. The males develop a larger third right arm that will be used in the mating process. Both sexes reach their adult size between twelve to fifteen months, right before reproducing. The male, displaying dark brown coloring with white spots, initiates courtship behavior by slowly approaching the female. He raises his modified arm upright waving it toward the female. If she is receptive, the male will insert his arm into the female’s oviducts passing her his spermatophores. The female will protect her newly laid eggs as they develop. She doesn’t eat after laying her eggs and will die about the same time as the eggs will be hatching. Males also die after mating.


Day octopuses are typically solitary.


This species’ greatest adaption is the ability to change their appearance in the blink of an eye to blend into its surroundings, thus avoiding predators. They may also squirt a cloud of black ink, which confuses predators allowing the octopus to jet away.


The typical lifespan of a day octopus is twelve to fifteen months.


Day octopus habitats are threatened by the effects of climate change on coral reefs.