According to ITIS, 33 species of fish belong to the genus Galaxias. They have a variety of common names. According to Fishbase, Galaxias brevipinnis is the koaro. Galaxias argenteus is the giant kokopu. Galaxias gracilis is the dwarf inanga. Galaxias auratus is the golden galaxias. Many common names have been applied to Galaxias maculatus. Spotted minnow is the one that I like the best, since the specific name maculatus means “spotted.” Other common names of this species are common galaxias, common jollytail, cowfish, eel gudgeon, inanga, native trout, slippery tarki, and whitebait.
Fish of the genus Galaxias belong to Animalia, the animal kingdom, and Chordata, the chordates. Depending on the classification used, it belongs to a class called Pisces, Osteichthyes, or Actinopterygii. Pisces is the plural of a Latin word meaning “fish,” so it is a convenient class name for these animals. Osteichthyes means “bony fish,” so sharks, rays, and skates are excluded when this occurs as a class name. Actinopterygii are ray-finned fishes, so fish with lobe fins are excluded when the class has this name.
In the lower taxa, the genus Galaxias belongs to the order Osmeriformes and the family Galaxiidae. Osmeriformes is the order to which true smelts and similar fishes belong. The members of the family Galaxiidae are generally called galaxiids. Galaxias is the type genus of the family. This means that the fishes in this genus are thought to possess characteristics that are most typical of the family.
In the foregoing paragraph, I have assigned Galaxiidae to the order that I personally prefer. However, an offline version of the Encyclopaedia Britannica places this family in the order Salmoniformes. This is also a good classification, since the life cycle of some galaxiids is similar to that of the salmons.
The following notes on the range of the genus Galaxias are mostly derived from data recorded by Fishbase.
Some species are confined to fresh water. For example, Galaxias auratus spends its entire life in a Lake Crescent and Lake Sorrel in Tasmania, as well as nearby rivers and marshes. In contrast, Galaxias maculatus is catadromous. This means that it lives in fresh water but descends to salt water to breed.
Many species have a restricted range. Galaxias gracilis (the dwarf inanga) Galaxias argenteus (the giant kokopu), Galaxias fasciatus (the banded kokopu), Galaxias paucispondylus (the alpine galaxias), Galaxias divergens, and others are endemic to New Zealand. Like Galaxias auratus, Galaxias fontanus (the swan galaxias) is endemic to the Australian island of Tasmania. Other Australian endemics are Galaxias olidus (the mountain galaxias) and Galaxias occidentalis (the western minnow), etc.
While most Galaxias endemics live in either New Zealand or Australia, Chile is the only country in which Galaxias globiceps has been found. Galaxias platei also occurs in the western hemisphere, but it is not an endemic. Its range includes Chile, Argentina, and the Falkland Islands.
Galaxias maculatus occurs in both the Eastern and Western Hemispheres. You may find it in Australia, New Zealand, Argentina, Chile, and the Falkland Islands.
As you may suspect after reading the data above, fishermen will not be able to catch any species of Galaxias in the North Sea or Puget Sound. The fish that belong to this genus live only in the southern hemisphere, according to the Encyclopaedia Britannica.
The fish in this genus do not reach a very large size. Even the giant kokopu achieves a maximum length of only 40 centimeters. In contrast, the maximum length of the dwarf inanga is 6.2 centimeters, and the corresponding figure for Galaxias neocaledonicus is even smaller: only 5.2 centimeters. Others are intermediate between these two extremes. For example, the western minnow achieves a maximum length of 19 centimeters, according to Fishbase.
According to the Australian government, fish of the genus Galaxias have no scales. The color and shape vary in different species. For example, Galaxias auratus, the golden galaxias, is “golden-amber in color with dark elliptical spots on its back and sides.” It has a stout body, a slender tapering head, and a forked tail.
In contrast, the body of Galaxias fontanus is light olive brown and silvery white below, with brownish spots, bars, or blotches on the sides, according to Fishes of Australia.
Fish of this genus typically feed on small invertebrates. For example, Galaxias auratus likes to feed on insect larvae and small crustaceans, such as water fleas of the genus Daphnia. Similarly, Galaxias maculatus preys on small insects, crustaceans, and mollusks.
The Encyclopaedia Britannica, 2010