Stenolebias is a small genus of killifish in family Rivulidae, native to Brazil. The atlas covers 2 species, both tiny - just 1–1.5 in - and, like many of its relatives in the seasonal-killifish tribes of this family, it is associated with temporary pools that dry out for part of the year. In that life history, adults lay eggs into the mud or leaf litter, the pool evaporates, and the eggs enter a resting diapause in the substrate until the next rains refill the habitat and trigger hatching - a strategy shared across much of Brazil's annual-killifish fauna.
This is a genus for specialist killifish keepers rather than the general trade - annual killifish of this kind are bred from eggs shipped in slightly moist peat rather than sold as living fish, and species like these two rarely if ever reach mainstream stores. The IUCN picture is mixed but not alarming at the assessed end: one species is Data Deficient and the other Least Concern, though small-range annual-pool species like these are inherently exposed to any loss of their seasonal wetland habitat, regardless of current status.