Blue-ringed octopus

Photo: uwkwaj · CC BY-NC

Found in sand and rubble at 6 to 20 m at Kontiki, the greater blue-ringed octopus is one of the most potently venomous animals in the ocean — its salivary tetrodotoxin has no antivenom. At rest, the animal is a dull mottled brown and easily overlooked; when disturbed, iridescent blue rings pulse rapidly across the skin as a warning. Despite their reputation they are non-aggressive and bite only when directly handled. Local guides know specific rubble patches where individuals are seen regularly. A compelling encounter for experienced macro photographers working under careful supervision.