Scientific name: Orestias cuvieri
Range: Lake Titicaca
When last seen: 1952
Suspected reason for disappearance: In 1937, 500,000 trout eggs were sent to Lake Titicaca, irreversibly altering the native ecosystem. There has been severe competition from introduced trout, including lake trout, brown trout, and rainbow trout, as well from Argentinian silverside from the 1930s to the 1950s. Pollutants have contaminated the water and traces of metals, such as zinc and copper have been found in the tissues of fishes. In addition, runoff from fertilisers and pesticides used in agriculture has been extremely toxic to the fish.
IUCN conservation status: Data Deficient
Facts: It is the largest member of the pupfish genus Orestias and, despite its name, it is not the only Orestias fish from Lake Titicaca. Orestias cuvieri is thought to be as old as 5 million years and is specifically adapted to its closed lake environment.
Size: Grows up to 27cm.