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Marine Animal Encyclopedia

Blue-ringed Octopus Hapalochlaena maculosa

The most dangerous cephalopod is the small blue-ringed octopus, which produces highly toxic saliva powerful enough to kill a human.

To catch prey, the blue-ringed octopus either releases saliva into the water and waits for the poison to take effect, or catches, bites, and injects prey directly. Its bright coloring is unusual for an octopus, and the numerous blue rings covering its body become more iridescent if it is disturbed.

Blue-ringed Octopuszoom image
  • Class Cephalopoda
  • Length 4–8 in (10–20 cm)
  • Habitat Shallow water, rock pools
  • Distribution Tropical west Pacific and Indian Ocean (all species of Hapalochlaena)
Blue-ringed Octopus habitat mapzoom image