Burnt-brown markings disjoined down the back like mismatched wallpaper. That is the roundhead galaxias, a small non-migratory fish confined to Otago. It grows to about 130 millimetres but rarely exceeds 90. A fish that stays small and stays local, never venturing to the sea. The roundhead occupies low-gradient streams from small weedy drains to braided cobble channels. It tolerates high water temperatures and low flows, surviving droughts by retreating to remnant pools in ephemeral streams. This resilience is both strength and vulnerability. The fish persists where others cannot, but those same harsh conditions limit its distribution to a narrow band of Central Otago. Spawning occurs in early spring. Eggs are laid amongst loose gravel and cobbles in riffles and at stream edges. Spawning sites are communal, with up to 40 individuals gathering in areas smaller than ten by ten centimetres. A mass spawning event in a space no bigger than a dinner plate. The larvae hatch and remain in freshwater, never undertaking the marine migration of their diadromous relatives. This non-diadromous life history means the species is entirely dependent on freshwater habitat quality. No ocean nursery exists. No marine phase provides refuge. The entire life cycle plays out in streams that farmers drain, foresters sediment, and developers modify. Sixteen caudal fin rays distinguish the roundhead from similar species. The dusky has fourteen. Eldon's has fifteen. These subtle differences matter to taxonomists but mean nothing to the trout that eat them. Introduced salmonids are the primary threat, along with habitat destruction from riparian vegetation loss and stream modification. Twelve confirmed local extinctions have occurred due to trout movement and invasion. Each extinction represents a population lost forever, a genetic lineage erased. The roundhead cannot recolonise from elsewhere. It does not migrate. It does not disperse widely. Once gone from a stream, it is gone permanently. Only 26 populations remain. The roundhead galaxias is classified as Nationally Vulnerable, critically endangered internationally. It lives in the Taieri and Clutha catchments, though records from the Pomahaka remain uncertain. A fish clinging to existence in shrinking pockets of suitable habitat, watching its world dry up and fill with predators it never evolved to escape. Conservation efforts focus on protecting remaining populations through trout exclusion barriers, riparian planting, and habitat restoration. But the window is narrowing. Each drought, each new trout incursion, each culvert installation brings the species closer to the edge. The roundhead galaxias is not yet extinct. But it is running out of places to hide.