阿氏山鮰

The <em>Orestias agassizii</em> is a freshwater fish belonging to the family Cyprinodontidae, the killifishes — a group renowned for their physiological resilience and wide environmental tolerances. Adults typically reach a maximum length of around 7 cm. This species is notably associated with the high-altitude lakes and rivers of the Andean altiplano in South America, particularly Lake Titicaca and its surrounding watershed, which sits at an elevation of approximately 3,810 metres above sea level. The genus <em>Orestias</em> is an ancient lineage with no close relatives in adjacent lower-elevation drainages, having diversified in relative isolation over millions of years in the high Andes. <em>Orestias agassizii</em> is named in honour of the naturalist Louis Agassiz and represents one of the most studied species within this endemic radiation. Details of habitat and range for this species remain limited in the ichthyological literature for some populations. Threats to the species include introduced trout, habitat degradation from agricultural runoff and urban expansion around Lake Titicaca, and climate change affecting glacier-fed tributary systems. The species plays an important ecological role in the lake ecosystem and holds cultural significance for indigenous Andean communities for whom it has historically been a food source.