Found mainly in tidal rock pools around Australia, the Blue Ringed Octopus are easily identifiable by the distinctive blue rings, hence its name. The venom contains tetrodotoxin, that is enough poison to kill more than 20 adults within minutes. Effects of neurological problems include numbness or paraesthesia, weakness, breathing difficulties, paralysis and unable to respond, sometimes with fixed dilated pupils. The first aid used for this type of bite is the pressure-immobilisation technique, firm pressure is applied over the bitten area and the limb is immobilised. The patient should be immediately taken to the nearest medical centre.

— Hapalochaena fasciata is one of 3 or 4  species of Blue-ringed octopuses, most commonly found around intertidal rocky shores and coastal waters to a depth of 15 m between southern Queensland and southern New South Wales. Its mantle can grow up to 45 mm and has yellow coloration with dark blue/black streaks covering the whole body, except for the underside of the tentacles.