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Blue-ringed Octopus | Daily Animal Facts

Animal profile

Blue-ringed Octopus

Hapalochlaena maculosa

CephalopodaShallow tide pools, rubble and seagrass beds in temperate and tropical Indo-Pacific waters

Field profile

Blue-ringed octopuses are small, golf-ball-sized animals that flash iridescent blue rings when disturbed. Their saliva contains tetrodotoxin, the same paralytic toxin found in pufferfish, making them among the few octopuses genuinely dangerous to humans.

Scope note

This is an editorial profile, not a diagnostic field-identification guide or a substitute for current conservation assessments. Follow the cited sources on each fact for the evidence trail.

Published field notes

2026-01-01

Blue-ringed Octopus

The blue-ringed octopus does not make its own venom

Its paralytic tetrodotoxin is produced by symbiotic bacteria living in the octopus's salivary glands, not synthesised by the animal itself. The same compound appears in pufferfish and rough-skinned newts for the same reason.

Read with evidence →