Ophthalmolebias is a genus of annual killifish in the family Rivulidae, native to coastal Brazil. Its species share the seasonal-pool life history typical of the group: adults live and breed in temporary water bodies that dry up each year, and the species survives the dry season as eggs in diapause buried in damp substrate, hatching when the rains return. The atlas covers 2 species, Ophthalmolebias constanciae and O. perpendicularis, both modest fish of roughly 2–2.5 in.
O. constanciae, the featherfin pearlfish, is known in the specialist killifish hobby for the male's elaborate, trailing fin extensions and vivid colouration, making it a prized if demanding species for keepers experienced with peat-based annual breeding. Both species in the genus are Critically Endangered, among the most acute conservation concerns in the atlas's killifish coverage, and one is flagged in the CARES conservation-priority list - a reminder that hobbyist breeding can matter directly for species survival given how restricted coastal Brazilian seasonal-pool habitat has become.