Midring blue ringed octopus

Scientific name : Hapalochlaena sp.

Small octopus, with short tentacles and pointed body. Typical colour pattern, with medium size blue rings that can be hidden but usually are shown clearly when a diver is close, as warningcolour. Body 3 cm, tentacles 5 cm. Confusion possible with Hapalochlaena lunulata, identified by the larger blue rings. Hapalochlaena species host in their salivar glands symbiotic bacteria, responsible for the production of the deadly tetrodotoxin (the same toxin produced by puffer fishes). This venom kills through the progressive (reversible) paralysis of all the volunteer muscles. The death is by repiratory paralysis, and can be avoided by artificial breathing.
It is worth saying that this species is absolutely not aggressive, and the venomous byte is used only as last option.