Kingdom Animalia Subfamily Galaxiinae Scientific name Galaxias rostratus Higher classification Galaxias Order Osmeriformes | Family Galaxiidae Genus Galaxias Phylum Chordata Rank Species | |
The flathead galaxias (Galaxias rostratus) is a freshwater fish found in lowland rivers and streams and associated billabongs, backwaters, etc. of the southern Murray-Darling river system in Australia.
Contents
Flathead galaxias continue a pattern found in Murray-Darling native fish of speciation into upland and lowland habitats. Flathead galaxias are found in lowland habitats, while the mountain galaxias species complex, containing at least seven species of Galaxias (research is ongoing) are found in upland habitats, as well as "midland" or upland/lowland transitional habitats.
Morphology
The fish is similar in appearance to the common galaxias, except with a distinctly flattened head, larger eyes and longer snout. It has an olive green back and sides with indistinct grey to green blotches and silvery bottom. Adults are commonly 9 cm but found up to 12 cm long.
Conservation
Serious concerns exist for flathead galaxias. They, along with a number of other small native forage fish, are disappearing from vast tracts of the Murray-Darling basin. The species is considered extinct in South Australia. Along with river regulation, destruction of water clarity and submergent macrophytes ("water weed") by exotic, illegally introduced common carp (Cyprinus carpio) appear to be having a devastating effect on this species. Many or all of the small native forage fish of the southern Murray-Darling system apparently used these weeds beds for shelter, feeding, and spawning sites.