Octopus cyanea (Gray, 1849)
Common in the Solitary Islands Marine Park. Distributed throughout the tropical Indian and Pacific Oceans. In Australia recorded from northern New South Wales across the tropical north to around Perth in Western Australia.
Frequents coral reef and rubble areas from intertidal reef flats to at least 30m depth. They are active during daylight hours and inquisitive, interacting with divers on occasions.
This octopus is recognisable by its large muscular arms and deep web, the arms often having rows of white spots. The skin has a fine creased texture that can be raised into spikes or lumps over the body and upper arms, it is able to change colour and appearance almost instantaneously. Living in crevices in the coral, the lair is recognisable by the scattering of empty crab and mollusc shells adjacent. Uses its excellent camouflage to hunt as an ambush predator, by stalking its prey or covering small areas with its large web and using its arm tips to scare small fish or invertebrates into its suckers. Females lay up to six hundred thousand tiny eggs which it cares for until they hatch, after which the mother dies. The young are planktonic.
It has a body around 20cm long with arms up to a metre in length.