A postdoctoral research fellow at the Australian Museum, Hiroyuki Motomura, has announced the discovery of the creature - whose closest relatives, like Nemo, all live in tropical and subtropical waters nearly 1000 kilometres to the north.



Dr Motomura was so surprised that he named the five centimetre long, prickly fish species Insperatus, which is derived from the Latin word for unexpected.

Only two specimens of the fish have been collected - both from water controlled by the navy at Chowder Bay in 2001.

The collections were made as part of a survey for the Sydney Ports Corporation. At the time no one realised the significance of the find and assumed the two fish were small individuals of the common red rockcod.