Pterolebias is a genus of killifish from the family Rivulidae which are native to temporary swamps and ponds in South America. It includes two groups, which sometimes are regarded as separate genera: Pterolebias (sensu stricto) from the southern Amazon and Paraguay (including the Pantanal) river basins, and Gnatholebias from the Orinoco (including the Llanos) river basin.

Depending on the exact species, these annual killifish reach up to 7–12 cm (2.8–4.7 in) in total length.

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