Aquatic insects form the bulk of its diet. Terrestrial items falling into water are taken opportunistically. Small crustaceans supplement intake during certain seasons. It feeds primarily on drifting prey caught in current or picked from substrate surfaces in shaded stream sections. The gollum galaxias lives in lowland streams across Southland. These waters flow slowly through pastoral land, bordered by willows and pasture grass rather than native bush. The fish prefers sections where overhanging banks create shade and submerged roots offer hiding places from predators. Dense riparian vegetation is critical. Without it, the water warms, algae blooms, and the fish becomes visible to everything that hunts it. Named after the Tolkien character for its large eyes and preference for dark, sheltered habitats, the gollum reaches about 100 millimetres in length. Its body is slender, coloured brownish-grey with irregular darker markings along the sides. Fifteen caudal fin rays distinguish it from similar species. The roundhead has sixteen. Eldon's has fifteen but differs in other morphological features. Taxonomic precision matters when conservation resources target specific populations. Spawning occurs in spring. Eggs are laid amongst gravel and debris in shallow water. The larvae remain in freshwater, never migrating to sea. This non-diadromous life history makes the species entirely dependent on maintaining suitable freshwater habitat year-round. There is no marine phase to provide refuge if streams degrade. No ocean nursery exists to replenish populations lost to local extinction. Threats come from multiple directions. Introduced trout patrol the same waters, eating juvenile and adult gollums alike. Habitat modification through drainage, culvert installation, and riparian clearing removes the cover the fish needs. Sediment from agricultural runoff smothers spawning gravels. Water extraction reduces flows, concentrating predators and raising temperatures beyond tolerable limits. Each threat compounds the others. Remove the vegetation and the water warms. Warm the water and the trout thrive. Add sediment and the eggs suffocate. The gollum persists in shrinking pockets of suitable habitat, clinging to existence in streams that farmers drain and developers modify. Conservation efforts focus on protecting remaining populations through riparian planting, trout exclusion, and habitat restoration. But the window narrows with each passing season. The gollum galaxias is not yet extinct. But it requires intervention to survive.