Acantholebias is a small genus of South American annual killifish, part of the pearlfish group historically associated with the wider Austrolebias radiation of temporary-pool specialists in Brazil and Uruguay. The 2 species in the atlas run 2 in and follow the classic annual-killifish life history: eggs are laid in the mud at the bottom of seasonal pools that dry out completely, surviving in a dormant diapause state through the dry season and hatching once the rains refill the habitat, packing an entire life cycle into a single wet season.
The genus is known mainly to specialist killifish keepers who work with annual species and their distinctive peat-incubation breeding method rather than the general aquarium trade. Between the 2 species, the yellow-spotted pearlfish (Acantholebias luteoflammulatus) and A. quirogai, the IUCN tally runs 1 Near Threatened and 1 Endangered, consistent with the vulnerability of fish confined to small, temporary wetland habitats that are easily lost to drainage or land conversion.