Octopus cyanea
Encounter Rate
Spotting Difficulty
Best Season
Year-round
Depth Range
1-40 meters
The reef octopus, also known as the day octopus or big blue octopus, is the most commonly encountered octopus species in Komodo National Park and one of the most intelligent invertebrates on the reef. Reaching arm spans of up to one metre, this active and bold cephalopod is one of the few octopus species that hunts predominantly during the day, making it far more visible to divers than its nocturnal relatives. In Komodo, reef octopuses are regularly seen flowing across the reef in a remarkable display of colour and texture changes, their bodies morphing in real time to match coral, sand, algae, or rubble with astonishing precision. They hunt by parachuting their web of arms over coral heads to trap fish and crustaceans hiding within, and are known for their problem-solving intelligence, using tools and even carrying coconut shells as portable shelters. Their den is usually marked by a midden pile of discarded crab and shell fragments outside the entrance — a telltale sign for observant divers and their guides.
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Average Size
40-60cm arm span
Size Range
20cm-1m arm span
Maximum Size
1m arm span
Active daytime hunter feeding on crabs, shrimp, small fish, and molluscs. Uses its web of arms to parachute over coral heads and trap prey hiding within the branches.
The reef octopus, also known as the day octopus or big blue octopus, is the most commonly encountered octopus species in Komodo National Park and one of the most intelligent invertebrates on the reef. Reaching arm spans of up to one metre, this active and bold cephalopod is one of the few octopus species that hunts predominantly during the day, making it far more visible to divers than its nocturnal relatives. In Komodo, reef octopuses are regularly seen flowing across the reef in a remarkable display of colour and texture changes, their bodies morphing in real time to match coral, sand, algae, or rubble with astonishing precision. They hunt by parachuting their web of arms over coral heads to trap fish and crustaceans hiding within, and are known for their problem-solving intelligence, using tools and even carrying coconut shells as portable shelters. Their den is usually marked by a midden pile of discarded crab and shell fragments outside the entrance — a telltale sign for observant divers and their guides.
This species plays an important role in the marine ecosystem of Komodo National Park. Responsible diving practices help protect these animals and their habitat for future generations.
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Look for a patch of reef that seems to shift or shimmer slightly — that may be an octopus mid-colour change. Also look for shell middens (piles of crab shells) outside crevices, which indicate a den is nearby.
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