Great Barrier Reef . Australia
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DANGERS ON THE REEF.....Blue Ring Octopus

Blue Ring Octopus

There are two species of blue-ringed octopus: 

1. Hapalochlaena lunulata, which is the larger and grows up to 20cm (8 in) across its stretched tentacles. 

2. Hapalochlaena maculosa, is small and more common, weighing a mere 28 grams (1 oz). They are found in the shallow coral and rock pools of Australia. 

While resting, the Blue Ring Octopus is a pale brown to yellow colour. The blue rings on its body only "light up" as a warning when the animal feels threatened. 
Don't pick one up - by the time you see the electric-blue rings, it's too late!


  • It starts life the size of a pea and is fully grown at about the size of a golf ball.
  • They have a life span of approx. 2 years.
  • Carry enough poison to kill 26 adults within minutes.


Southern Western Australia, to southern Qld and northern Tasmania


The Blue Ring Octopus is not an aggressive animal and when disturbed it flattens out its body to hide and changes its body colour to blend into its surroundings.


They are soft-bodied animals, with a sack-like body and eight arms covered with suckers. 


The female lays approximately 50 eggs in late Autumn. She carries her eggs around under her arms. Once the eggs have hatched after 3 - 6 months, the female dies. The young octopus develop rapidly, mature and mate early the following Autumn. The males then die and the female broods the eggs. 


The Blue Ring Octopus hunts during the day. It eats invertebrates and wounded fish.

General Information:

With a beak that can penetrate a wet-suit, they are one little cute creature to definitely look at BUT Don't touch. 

The bite might be painless, but this octopus injects a neuromuscular paralysing venom. The venom contains some maculotoxin, a poison more violent than any found on land animals. The nerve conduction is blocked and neuromuscular paralysis is followed by death. The victim might be saved if artificial respiration starts before marked cyanosis and hypotension develops. The blue-ringed octopus is the size of a golf ball but its poison is powerful enough to kill an adult human in minutes. There's no known antidote. The only treatment is hours of heart massage and artificial respiration until the poison has worked its way out of your system.

The venom contains tetrodotoxin, which blocks sodium channels and causes motor paralysis and occasionally respiratory failure. Though with fixed dilated pupils, the senses of the patients are often intact. The victims are aware but unable to respond.

Although the painless bite can kill an adult, injuries have only occurred when an octopus has been picked out of its pool and provoked or stepped on.


  • Onset of nausea. 
  • Hazy Vision. ( Within seconds you are blind.)
  • Loss of sense of touch, speech and the ability to swallow. 
  • Within 3 minutes, paralysis sets in and your body goes into respiratory arrest.

The poison is not injected but is contained in the octopus's saliva, which comes from two glands each as big as its brain. Poison from the one is used on its main prey, crabs, and is relatively harmless to humans. Poison from the other gland serves as defense against predators. The blue-ringed octopus either secretes the poison in the vicinity of its prey, waits until it is immobile and then devours it, or it jumps out and envelops the prey in its 8 tentacles and bites it.

First Aid

First aid for blue-ringed octopus bites

Pressure-immobilization is a recommended first aid. Prolonged artificial respiration may also be required. May require supportive treatment including mechanical ventilation until the effects of the toxin disappear. There is no antivenin available in Australia.
Mouth to mouth resuscitation can keep the victim alive and the poison gradually wears off after 24 hrs, apparently leaving no side effects.

blue ring octopus. Picture copywrite

Electric Blue rings that glow when the animal is provoked. 
This is when it looks pretty but is the most lethal. Do not touch! 
Image ©


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