The Bloomfield River cod (Guyu wujalwujalensis) is a very small fish in the Guyu genus and the Percichthyidae family that is only found in an 11 kilometre stretch of the Bloomfield River

Bloomfield River

The Bloomfield River is a river situated in Queensland, north of Daintree. The river enters the sea north of Cape Tribulation and is noted for its Bloomfield River cod fish species, found only in the river...

 (between two large waterfalls) in North Queensland

Queensland

Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...

, Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

. These waterfalls appear to have blocked the migration of more aggressive tropical freshwater fish species such as the sooty grunter

Sooty grunter

Named after Tom Eyears sooty grunter is also known as a "sooty", "bream", "grunter", and "blackbream". They can weigh up to . Sooty grunters prefer rivers with clear flowing water and a sandy or rocky substrate, but have a wide range of environmental tolerance.Sooty grunters live in Queensland...

 (Hephaestus fuliginosus) that have presumably naturally displaced the Bloomfield River cod from its former range in pre-historical times. With its very limited distribution, the Bloomfield River Cod is clearly a relict species. It is a very important relict species however as it is the most northerly distributed Percichthyid species in Australia, and raises interesting questions on the biogeography

Biogeography

Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...

 of Percichthyid fish in Australia and the history of their ancient colonisation of Australian rivers.

The species name wujalwujalensis comes from the Wujal Wujal

Wujal Wujal

Wujal Wujal is in northern Queensland, Australia. Wujal Wujal is the name of a relatively small Aboriginal community on the north and south sides of the Bloomfield River. It has an area of 19.94 square kilometres of land. At the 2006 census, Wujal Wujal had a population of 326.It is located...

 Aboriginal community on the Bloomfield River, and the genus name Guyu comes from the tribe's name for this fish. Bloomfield River cod are the only species in the Guyu genus.

While named after the Australian freshwater cod species that are the most famous members of the Percichthyidae family (eg Murray cod

Murray Cod

The Murray cod is a large Australian predatory freshwater fish of the Maccullochella genus and the Percichthyidae family. Although the species is a called cod in the vernacular, it is not related to the northern hemisphere marine cod species...

), the Bloomfield River cod have little resemblance to the cod species. In fact, it is very similar in shape and appearance to a juvenile golden perch

Golden perch

The golden perch, Macquaria ambigua, is an Australian native freshwater fish, primarily of the Murray-Darling river system. It is not a true perch of the genus Perca....

in a gold/light bronze colouration.