Percichthyidae family ( The temperate perches )
The members of Percichthyidae family are known as the temperate perches. They belong to the Order Perciformes or perch-like fishes.
The name Percichthyidae derives from the Ancient Greek words Perca for 'perch' and ichthyos for 'fish' and translated basically means perch-like fishes.

Classification
The temperate perches are closely related to the temperate basses of the Moronidae Family, and older literature treats the latter as belonging to the Percichthyidae Family.
Australian freshwater Percichthyids were once placed in the Serranidae family, and the two families are considered to have some link to each other. The Serranidae family contains about 450 species of serranids in 64 genera, including the sea basses and the groupers (subfamily Epinephelinae).

Species
Australia has the greatest number of Percichthyid species, they are represented by fishes including bass, blackfish, cod and perch.
Nearly all the Percichthyidae fishes in Australia are fresh water to brackish water fishes, and most can be found in temperate waters, except for the Bloomfield river cod (Guyu wujalwujalensis) which is found in tropical waters.

Alarming low numbers
The Australian Percichthyidae family of fishes have not fared well since European settlement of Australia, and native fish numbers have plummeted to alarming low numbers. Some species that may have been a separate species or sub-species, Richmond River Cod and Brisbane River Cod, have already been lost, and a number of other species are listed as endangered or critically endangered.

Species of Percichthyidae under threat include the bloomfield river cod, which is only found in an 11 kilometer stretch of the Bloomfield River (between two large waterfalls) in North Queensland, Australia. These waterfalls appear to have blocked the migration of more aggressive tropical freshwater fish species such as the sooty grunter (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 of Percichthyid fish in Australia and the history of their ancient colonisation of Australian rivers.