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.[1]
Depending on the exact species, these annual killifish reach up to in total length.
There are four recognized species in Pterolebias according to FishBase, but two of these are sometimes placed in a separate genus, Gnatholebias. The two groups are relatively distantly related and if kept in a single genus Pterolebias is paraphyletic.[1] [2]