Sleek body tapering to a slender snout. Dark grey-brown colouration with creamy gold bars. That is Eldon's galaxias, named for G.A. Eldon who assisted Dr R.M. McDowall with his investigations into the Galaxiidae. A fish honouring a man who studied fish, now itself studied by those trying to prevent its disappearance. Eldon's reaches a maximum size of about 150 millimetres, commonly found up to 110. It inhabits tributaries of the lower to mid-Taieri River catchment, with a highly fragmented distribution. Competition from introduced salmonids has likely caused this fragmentation. Brown trout, rainbow trout, and brook char patrol the lower reaches, forcing Eldon's upstream. Land-locked populations of native koaro in Lake Mahinerangi may also affect distribution. The fish exists in isolated pockets, separated by barriers it cannot cross and predators it cannot evade. The fish prefers riffle habitats but can be found in pools. It occupies diverse streams from high-altitude tussock country to low-altitude forested valleys. Often it is found upstream of large waterfalls that restrict trout distribution. These natural barriers provide refuge, creating isolated pockets where Eldon's persists. Fifteen caudal fin rays distinguish it from similar species. The flathead has sixteen. The dusky has fourteen. Taxonomic precision matters when conservation resources are limited. Knowing which species is which determines which streams receive protection and which are left to the trout. Spawning occurs in mid-spring. Larvae hatch about a month later. Like most non-diadromous galaxiids, Eldon's feeds on aquatic insects, occasional terrestrial items, and on rare occasions small koura. It can often be seen during the day feeding on items drifting downstream. A visible fish in clear water, making it easy to spot and easy to target. This visibility is a double-edged sword. Researchers can monitor populations. Predators can find them too. Classified as Nationally Vulnerable, Eldon's galaxias faces the same threats as its Otago relatives. Riparian vegetation destruction, habitat modification, and introduced predators combine to squeeze remaining populations. The distribution is restricted, the threats are known, and the solutions are difficult. Protect waterfalls. Remove trout. Restore vegetation. Simple in theory. Complex in practice. Each remaining population represents a genetic reservoir, a potential source for recolonisation if barriers can be removed and predators controlled. But time is short. The trout are patient. The galaxias is not.