Common river galaxias

Species of fish

The common river galaxias or Canterbury galaxias (Galaxias vulgaris) is a galaxiid fish of the genus Galaxias, found only in Canterbury, New Zealand.

Galaxias vulgaris are a small freshwater fish which usually grow to 100–115 mm in length. They have a large mouth with a somewhat undercut lower jaw, pinched nostrils and a rounded snout. The fins are thick and fleshy. The pectoral fins are low and downturned. The caudal peduncle long and slender, the length of which is about 1.5 times the depth. This pigmentation is so effective as a camouflage, that it allows them to move out from the sanctuary under the rocks and spend time in the more open river in relative safety. They are easily confused with koaro which are slightly angled towards each other, but the eyes of G. vulgaris are larger and angled towards each other so the eyes are more visible when viewed from above. It is no longer found in many of the main river systems due to predation from introduced trout species Oncorhynchus mykiss (rainbow trout), and Salmo trutta (brown trout).

Preferred habitat of Galaxias vulgaris is fast flowing sections of stream which are well aerated and with open tussock grassland. Here, they inhabit the areas between and under rocks during the day and venture out into the more open areas of water to feed in the evening and night as Galaxias vulgaris generalized is solitary, nocturnal and largely cryptic invertebrate predator.

Unlike many other species in the genus, Galaxis vulgaris is a non migratory species and complete their entire life cycle in freshwater. Spawning occurs from August to September. This involves the females laying hundreds to thousands of eggs beneath boulders in the stream, (the number of eggs laid is dependent of favourable or unfavourable environmental conditions) and the male fertilizing and temporarily guarding the eggs. Also in 2014 the IUCN rated the SPECIES as "Least Concern", noting that rates of decline are slow. The ranges where the Galaxias vulgaris inhabit are with in New Zealand's Department of Conservation managed areas which means that these areas are protected, though there is still a large threat from the invasive salmonids. Habitat loss due to increasing irrigation from agricultural land use change is a threat to Galaxias vulgaris. The International Union for Conservation of Nature notes that there is an increased risk of habitat loss post tenure review in the high country. Much of the land which became freehold incorporates the habitat of Galaxias vulgaris and now has the potential to be altered for farming purposes, endangering the habitat of Galaxias vulgaris. Galaxias vulgaris is however classified as Not Threatened.