Blue ringed octopus

Pressure-immobilisation first aid is recommended for blue ringed octopus envenomation. Prolonged artificial respiration may be required following a bite. Envenomations may require supportive treatment including mechanical ventilation until the effects of the venom wear off. There is no antivenom available for blue ringed octopus envenomation.

Blue ringed octopus venom contains tetrodotoxin, which blocks sodium channels. This results in motor paralysis and occasionally respiratory failure. The patient may be completely paralysed and unable to respond, sometimes with fixed dilated pupils, but the sensorium is often intact (i.e., the patient may be aware, but unable to move or respond).