An Australian Blue Ringed Octopus flashes its iridescent blue rings. The rings really are as bright as this photograph. The Octopus uses the bright colour as some other species do to warn other animals of its dangerous venomous bite.

• Hapalochlaena maculosa
• It grows to a maximum length of 200mm when totally spread, and most are shorter than this. The octopus has a mass of 10-100g and is about the size of a golf ball
• The Blue Ringed Octopus can be found in shallow reefs and tide pools
• It can be found at depths ranging from 0 to 20 m
• It is not yet known whether the octopus simply secretes saliva near prey, and waits for it to become incapacitated, or if it actually bites its prey. Once the prey is dead, the octopus begins consuming it with its powerful beak-like mouth
• The life expectancy of a Blue-ringed octopus is about 2 years

More information about blue ringed octopus may be found at the Australian Museum Online.

A smaller version of this image is on the aquarium dive site page.