Garcialebias is a genus of South American annual killifish, part of the pearlfish assemblage in family Rivulidae historically grouped with Austrolebias. The atlas' 3 species - including the multi-colored pearlfish (G. viarius) - reach only about 1.5–3 in and are known solely from Uruguay and adjoining parts of southern Brazil, where they live in temporary pools and marshes on the Rio de la Plata grasslands. Like other annual killifish, they complete their life cycle in the brief window a pool holds water: eggs laid in the mud survive the dry season in diapause and hatch when the rains refill the pool.
Garcialebias is essentially a specialist-hobby fish - kept and bred from dried, peat-stored eggs by killifish enthusiasts rather than sold as a mainstream aquarium species - and a genus of real conservation concern. All three species in the atlas are assessed Endangered, reflecting how much of the seasonal pampas wetland habitat they depend on has been drained or converted to agriculture across Uruguay and southern Brazil. Ex-situ breeding by killifish hobbyists is a meaningful part of keeping these fish from disappearing entirely.