The Cape galaxias (''Galaxias zebratus'') is a species of freshwater fish of the

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

Galaxiidae The Galaxiidae are a family of mostly small freshwater fish in the Southern Hemisphere. The majority live in Southern Australia or New Zealand, but some are found in South Africa, southern South America, Lord Howe Island, New Caledonia, and th ...

. It is a small fish, rarely larger than 6 cm, that inhabits clear streams, rivers and ponds of South Africa. It shares the same habitat as imported

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-salmoni ...

and

bass Bass or Basses may refer to: Fish * Bass (fish), various saltwater and freshwater species Music * Bass (sound), describing low-frequency sound or one of several instruments in the bass range: ** Bass (instrument), including: ** Acoustic bass gui ...

species and has been identified as prey. The numbers of this relatively delicate fish have declined around

Cape Town Cape Town ( af, Kaapstad; , xh, iKapa) is one of South Africa's three capital cities, serving as the seat of the Parliament of South Africa. It is the legislative capital of the country, the oldest city in the country, and the second largest ...

. Although in South Africa it was at one time classified as

near threatened A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify fo ...

, in Australia species of the same genus were driven to

extinction Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

by competing

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 whitefis ...

s and other

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...

of fish. It is now classified as "

Data Deficient A data deficient (DD) species is one which has been categorized by the International Union for Conservation of Nature (IUCN) as offering insufficient information for a proper assessment of conservation status to be made. This does not necessaril ...

" on the grounds that the taxonomic status of the

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

is unclear.

Description

The Cape galaxias is a small slender fish with a cylindrical body and no scales. It has a single dorsal fin with 9 to 13 soft rays set well back on the body and just above the anal fin which has a similar number of rays. It is silvery in colour and the internal organs can be seen through the skin.

Distribution and habitat

Genus ''

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

'' is restricted to the Southern Hemisphere and the Cape galaxias is unique because it is the only species of the genus found in the

African continent Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the

Western Cape The Western Cape is a province of South Africa, situated on the south-western coast of the country. It is the fourth largest of the nine provinces with an area of , and the third most populous, with an estimated 7 million inhabitants in 2020 ...

region in South Africa and the first specimen caught by scientists was captured in the

Cape Flats The Cape Flats ( af, Die Kaapse Vlakte) is an expansive, low-lying, flat area situated to the southeast of the central business district of Cape Town. The Cape Flats is also the name of an administrative region of the City of Cape Town, which lie ...

area in 1861. For a long time it was believed that the distribution of this fish species was restricted to the

, within an area ranging between the

Keurbooms River The Keurbooms River ( af, Keurboomsrivier) is a river in the Western Cape Province in South Africa. The river has its sources south of Uniondale in the Langkloof and flows in a roughly southeastern direction. It passes De Vlugt and the Prince A ...

and the Olifants River. However, since 1995 it has been also found in the

Krom River Krom River or Kromme River ( af, Krommerivier) is a river in the Eastern Cape Province in South Africa. The river flows into the Indian Ocean through an estuary on the north side of St Francis Bay, west of Port Elizabeth. The Krom river flows in ...

as well as in the

Gamtoos River Gamtoos River or Gamptoos River is a river in the Eastern Cape Province, South Africa. It is formed by the confluence of the Kouga River and the Groot River (Eastern Cape), Groot River and is approximately long with a catchment area of . Cours ...

system of the

Eastern Cape The Eastern Cape is one of the provinces of South Africa. Its capital is Bhisho, but its two largest cities are East London and Gqeberha. The second largest province in the country (at 168,966 km2) after Northern Cape, it was formed in ...

.Freshwater Ichthyology - The Cape galaxias Galaxias zebratus
/ref> Some of the taxa in the complex are found in clear mountain streams with low dissolved mineral levels but others seem to prefer lowland streams that can be turbid and have high levels of dissolved minerals.

References

External links

{{Taxonbar, from=Q44199 Galaxias Taxa named by François-Louis Laporte, comte de Castelnau Freshwater fish of South Africa Fish described in 1861