''Galaxias'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of small

freshwater fish Freshwater fish are those that spend some or all of their lives in fresh water, such as rivers and lakes, with a salinity of less than 1.05%. These environments differ from marine conditions in many ways, especially the difference in levels o ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Galaxiidae, and are frequently referred to as the galaxiids. These highly adaptable fish are typically found at

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout ...

latitudes across the Southern Hemisphere. Galaxiids are scaleless and somewhat tubular in body form, ranging from very slender to quite bulky. They are somewhat torpedo-shaped, with the

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal c ...

and

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as see ...

s positioned close to the tail. They are generally small, with typical adults ranging between in total length, with some stocky species attaining around . The largest, ''Galaxias argenteus'', has been recorded at , although is a more typical adult length.

Species

The 46 recognized species in this genus are: * '' Galaxias aequipinnis'' Raadik, 2014 (East Gippsland Galaxias) * '' Galaxias anomalus'' Stokell, 1959 (Roundhead Galaxias) * '' Galaxias arcanus'' Raadik, 2014 (Riffle Galaxias) * '' Galaxias argenteus'' Gmelin, 1789 (Giant Kōkopu) * '' Galaxias auratus'' Johnston, 1883 (Golden Galaxias) * ''

Galaxias brevipinnis The climbing galaxias or kōaro (''Galaxias brevipinnis'') is a fish of the family Galaxiidae found in Australia, New Zealand, and nearby islands. The name climbing galaxias is used in Australia, and koaro or kōaro in New Zealand. Further verna ...

'' Günther, 1866 (Climbing Galaxias) * '' Galaxias brevissimus'' Raadik, 2014 (Short-tail Galaxias) * '' Galaxias cobitinis'' McDowall & Waters, 2002 (Lowland Long-jawed Galaxias) * '' Galaxias depressiceps'' McDowall & Wallis, 1996 (Flathead Galaxias) * '' Galaxias divergens'' Stokell, 1959 (Dwarf Galaxias) * '' Galaxias eldoni'' McDowall, 1997 (Eldon's Galaxias) * ''

Galaxias fasciatus ''Galaxias'' is a genus of small freshwater fish in the family Galaxiidae, and are frequently referred to as the galaxiids. These highly adaptable fish are typically found at temperate latitudes across the Southern Hemisphere. Galaxiids are ...

Gray Grey (more common in British English) or gray (more common in American English) is an intermediate color between black and white. It is a neutral or achromatic color, meaning literally that it is "without color", because it can be compose ...

, 1842 (Banded Kōkopu) * '' Galaxias fontanus'' Fulton, 1978 (Swan Galaxias) * '' Galaxias fuscus'' Mack, 1936 (Barred Galaxias) * '' Galaxias globiceps'' Eigenmann, 1928 * '' Galaxias gollumoides'' McDowall &

Chadderton Chadderton is a town in the Metropolitan Borough of Oldham, Greater Manchester, England, on the River Irk and Rochdale Canal. It is located in the foothills of the Pennines, west of Oldham, south of Rochdale and north-east of Mancheste ...

, 1999 (Gollum Galaxias) * '' Galaxias gracilis'' McDowall, 1967 (Dwarf Inanga) * '' Galaxias gunaikurnai'' Raadik, 2014 (Shaw Galaxias) * '' Galaxias johnstoni''

Scott Scott may refer to: Places Canada * Scott, Quebec, municipality in the Nouvelle-Beauce regional municipality in Quebec * Scott, Saskatchewan, a town in the Rural Municipality of Tramping Lake No. 380 * Rural Municipality of Scott No. 98, Sask ...

, 1936 (Clarence Galaxias) * '' Galaxias lanceolatus'' Raadik, 2014 (Tapered Galaxias) * '' Galaxias longifundus'' Raadik, 2014 (West Gippsland Galaxias) * '' Galaxias macronasus'' McDowall & Waters, 2003 * '' Galaxias maculatus'' Jenyns, 1842 (Common Galaxias) * '' Galaxias mcdowalli'' Raadik, 2014 (McDowall's Galaxias) * '' Galaxias mungadhan'' Raadik, 2014 (Dargo Galaxias) * '' Galaxias neocaledonicus''

Weber Weber (, or ; German: ) is a surname of German origin, derived from the noun meaning " weaver". In some cases, following migration to English-speaking countries, it has been anglicised to the English surname 'Webber' or even 'Weaver'. Notable pe ...

& de Beaufort, 1913 * '' Galaxias niger''

Andrews Andrews may refer to: Places Australia *Andrews, Queensland *Andrews, South Australia United States * Andrews, Florida (disambiguation), various places *Andrews, Indiana * Andrews, Nebraska *Andrews, North Carolina *Andrews, Oregon *Andrews, Sout ...

, 1985 (Black Galaxias) * '' Galaxias occidentalis'' Ogilby, 1899 (Western Galaxias) * '' Galaxias olidus'' Günther, 1866 (Mountain Galaxias) * '' Galaxias oliros'' Raadik, 2014 (Obscure Galaxias) * '' Galaxias ornatus'' Castelnau, 1873 (Ornate Galaxias) * '' Galaxias parvus'' Frankenberg, 1968 (Small Pedder Galaxias) * '' Galaxias paucispondylus'' Stokell, 1938 (Alpine Galaxias) * '' Galaxias pedderensis'' Frankenberg, 1968 (Pedder Galaxias) * '' Galaxias platei''

Steindachner Franz Steindachner (11 November 1834 in Vienna – 10 December 1919 in Vienna) was an Austrian zoologist, ichthyologist, and herpetologist. He published over 200 papers on fishes and over 50 papers on reptiles and amphibians. Steindachner describ ...

, 1898 * ''

Galaxias postvectis ''Galaxias'' is a genus of small freshwater fish in the family Galaxiidae, and are frequently referred to as the galaxiids. These highly adaptable fish are typically found at temperate latitudes across the Southern Hemisphere. Galaxiids are ...

'' F. E. Clarke, 1899 (Short-jaw Kōkopu) * '' Galaxias prognathus'' Stokell, 1940 (Long-jaw Galaxias) * '' Galaxias pullus'' McDowall, 1997 (Dusky Galaxias) * '' Galaxias rostratus'' Klunzinger, 1872 (Flathead Galaxias) * '' Galaxias supremus'' Raadik, 2014 (Kosciuszko Galaxias) * '' Galaxias tantangara'' Raadik, 2014 (Stocky Galaxias) * '' Galaxias tanycephalus'' Fulton, 1978 (Saddled Galaxias) * '' Galaxias terenasus'' Raadik, 2014 (Roundsnout Galaxias) * '' Galaxias truttaceus''

Valenciennes Valenciennes (, also , , ; nl, label=also Dutch, Valencijn; pcd, Valincyinnes or ; la, Valentianae) is a commune in the Nord department, Hauts-de-France, France. It lies on the Scheldt () river. Although the city and region experienced a ...

, 1846 (Spotted Galaxias) * '' Galaxias vulgaris'' Stokell, 1949 (Common River Galaxias) * '' Galaxias zebratus'' Castelnau, 1861 (Cape Galaxias)

Distribution

Galaxiids are restricted to the Southern Hemisphere, and generally only occur in temperate latitudes. Only one species is known from

subtropical The subtropical zones or subtropics are geographical and climate zones to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately 35° north a ...

habitats. Galaxiids are the dominant group of native freshwater fish in

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...

, and, along with the

Percichthyidae The members of the family Percichthyidae are known as the temperate perches. They belong to the order Perciformes, the perch-like fishes. The name Percichthyidae derives from the Latin ''perca'' for perch and Ancient Greek ἰχθύς, ''ichthy ...

, one of two dominant groups of native freshwater fish in southeastern

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

. Only one of the species ('' G. zebratus'') is found in Africa, and only three ('' G. globiceps'', '' G. maculatus'', and '' G. platei'') are found in South America.

Habitat

Galaxiids are coolwater species, with many wholly freshwater species specialising in high-altitude upland streams (including very small streams), rivers, and lakes. Some galaxiids include a marine stage in their lifecycles where larvae are washed out to sea to develop, and return to rivers as juveniles. This type of diadromous

fish migration Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousa ...

is known as amphidromy. These species are consequently also found in low-altitude habitats, but frequently migrate to high-altitude reaches of river systems in their adult stage.

Threats

Wholly freshwater galaxiids are gravely threatened by exotic

salmonid Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes . It includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), chars, freshwater whitefi ...

species, particularly exotic

trout Trout are species of freshwater fish belonging to the genera '' Oncorhynchus'', '' Salmo'' and '' Salvelinus'', all of the subfamily Salmoninae of the family Salmonidae. The word ''trout'' is also used as part of the name of some non-salm ...

species, which prey heavily upon them and compete with them for food and habitat. This is a major concern, as exotic trout species have been introduced to many different land masses (e.g. Australia, New Zealand, South Africa) with no thought as to impacts on native fish such as galaxiids, and no attempt to preserve some exotic trout-free habitats for native fish.Biodiversity, Alien trout, and the "So what" attitude
/ref> In most situations, wholly freshwater galaxiids are unable to persist in the presence of exotic trout species, and many are now restricted to the few remaining trout-free habitats. Where these species are found in the presence of trout, the galaxiids usually consist entirely of individuals which dispersed there from an upstream trout-free population, and are not self-sustaining. Numerous localised extinctions of wholly freshwater galaxiid species (i.e. mountain galaxias) have been caused by the introduction of exotic trout species (including ongoing illegal stockings) and a number of wholly freshwater galaxiid species are threatened with extinction by exotic trout species and other exotic

salmonids Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes . It includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), chars, freshwater whit ...

. Introduced salmoniids also have a negative impact on diadromous galaxiids, competing with them for food and habitat, as well as preying on them. However, the impact is not as great and they appear to be able to persist in the presence of trout.

References

External links