The blue ringed octopus is a small brown octopus which develops brilliant blue ring-shaped markings when disturbed. The genus is found throughout Australia's coastal waters and contains H. maculosa (the southern blue ringed octopus) in southern regions, H. lunulata (the greater blue ringed octopus) in more tropical areas, and H. fasciata (the blue lined octopus) which is found along the east coast of Australia. This genus has been associated with severe envenomations resulting in respiratory failure and human fatalities. The blue ringed octopus is found in tidal rock pools and is very attractive, especially to children and tourists, who are at risk of envenomation when they pick up the octopus. Bites can also occur when the creature is trodden on by waders.
