Scientific name: Rhizosomichthys totae
Range: Lake Tota basin, Colombia
When last seen: 1957
Suspected reason for disappearance: In 1936, 100,000 rainbow trout eggs, imported from North America, were released into the lake. Cecil Miles – the man who first described the species – claimed this would cause the extinction of the fat catfish. In 1990, Colombian ichthyologist José Iván Mojica claimed the trout and the fat catfish lived in different parts of the lake, lending dispute to Miles’ claim.
IUCN conservation status: Critically Endangered
Facts: Possesses remarkable rings of extensive adipose tissues surrounding the body – the only freshwater catfish in the world that has fatty rings of this kind. It’s so greasy that it’s sometimes referred to as the ‘greasefish’, and locals to Lake Tota used to impale it on sticks, set it alight, and use it as a torch. Only 10 specimens have been recorded.
Size: Grows up to 15 cm.