How to spot the Greater Blue-ringed Octopus when scuba diving
Hapalochlaena lunulata
Found in shallow coastal waters, tide pools, and coral reefs from Japan down through the Philippines, Indonesia, Papua New Guinea, Vanuatu, and across northern and southern Australia.
Primarily nocturnal, hiding in crevices or under rocks during the day. Night dives or dusk dives offer the best chance. Seasonality might play a role (e.g., more active in warmer months in some areas like Anilao, Philippines - Nov/Dec & Apr/May considered best, but possible year-round).
Tropical and subtropical shallow waters (e.g., Anilao temps 25-28°C / 77-81°F).
Found in rubble, muck/sand, or shallow reef areas. Look carefully in small crevices, discarded bottles/cans, or under rocks. Very small (golf-ball size). Crucial Safety Note: Highly venomous (tetrodotoxin), potentially lethal bite. Observe only, never touch or provoke. Rings flash bright blue when agitated.
Worldwide observation of the Greater Blue-ringed Octopus
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Data sources
- Photos: Wikimedia Commons
- Distribution and specie data: GBIF (Global Biodiversity Information Facility)
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