Greater Blue-ringed Octopus

Superpower

Flashes glowing blue rings as a final warning before its deadly bite.

At a glance

Size

typically 10 cm, up to 20 cm

Lifespan

1–2 years

Depth

0–20 m

Habitat

Shallow reefs, rubble and tide pools.

Diet

Crabs and shrimp, paralysed with venomous saliva.

Can I eat it?

No — this one is not eaten.

Safety

• Dangerous9/10

  Tiny and calm, but a bite can stop your breathing within minutes. Never touch it.

• Venomous10/10

  Carries enough tetrodotoxin to kill several adults; there is no antivenom.

• Poisonous9/10

  Its tissues are loaded with the same deadly toxin.

Fun facts

• •Its venom is one of the deadliest known, with no antidote.
• •The blue rings only blaze bright when it feels threatened.
• •It is small enough to sit in your palm — which you must never do.