Fauna
Invertebrate

Day Octopus

Octopus cyanea

Also known as Big Blue Octopus, Cyane's Octopus, Common Reef Octopus

Active during daylight across Indo-Pacific coral reefs, the day octopus is an exceptionally clever hunter that uses dynamic camouflage to blend instantly with surrounding corals and sand. It maneuvers over reef structures, flaring its webbed arms to flush out hiding crabs and crustaceans before extracting them with precise suckers. When returning from a forage, it retreats into a snug crevice surrounded by a telltale midden of discarded shells.

DiurnalReef DwellerCamouflage Master
—observations
—countries
—peak records
Least ConcernConservation statusIUCN Red List categoriesLCNTVUENCREWEXLeast ConcernRed List categories, explained →
Diet & preyCrabs, Shrimp, Bivalves
Predators
  • Moray Eels
  • Reef Sharks
  • Groupers
ThreatsHabitat degradation, targeted fishing, climate change impacts on coral reefs
HabitatsCoral reefs, rocky substrate, shallow seagrass beds
Life span1–1.5 years
  1. FamilyOctopodidae
  2. SpeciesOctopus cyanea
Range data is not available yet.
Interaction riskLow
  1. Low
  2. Moderate
  3. High
  4. Very high
Why interaction risk is low
Possesses a sharp beak capable of delivering a painful bite if handled; observe from a respectful distance without touching.
Responsible observation
  • Spotting Dens: Look for scattered piles of empty crab carapaces and clam valves that mark active dens.
  • Watch Camouflage: Maintain a quiet presence near a moving individual to witness rapid color and texture shifts.
  • Maintain Distance: Avoid reaching into reef crevices or attempting to handle wild individuals.
Help improve the field guideSomething wrong?

Report a name, category, or profile issue for review.

Checking your Fauna account…