Acrolebias carvalhoi

Acrolebias carvalhoi is a small annual killifish belonging to the family Rivulidae, a group of freshwater fishes renowned for their remarkable adaptation to ephemeral aquatic habitats. Like other annual killifish, this species likely completes its entire life cycle within a single wet season, with eggs entering a dormant state (diapause) buried in substrate to survive the dry months before hatching when seasonal rains return. Acrolebias carvalhoi is found in South America, where it inhabits temporary pools, marshes, and seasonally flooded grasslands characteristic of its native range.

These habitats are inherently fragile and highly localized, making species like this killifish extremely vulnerable to any disruption of the hydrological cycle that sustains their breeding grounds. The species is classified as Critically Endangered (CR) by the IUCN, reflecting severe restriction in range and ongoing degradation of the seasonal wetlands it depends upon. Agricultural expansion, drainage of wetlands for farmland and cattle grazing, and alteration of natural flooding regimes have progressively reduced the availability of suitable breeding pools.

Because annual killifish are often confined to a handful of known localities, even small-scale habitat conversion can have outsized impacts on population persistence. Population trends remain unknown, underscoring the need for further field surveys and long-term monitoring to establish a reliable baseline. On a more encouraging note, the growing interest of aquarist and ichthyological communities in South American annual killifish has spurred targeted ex situ breeding programs, helping preserve genetic stock for species facing habitat loss.

Continued collaboration between regional conservation authorities, herpetological and ichthyological societies, and local landowners offers a promising pathway toward safeguarding the remaining wetland fragments this species relies upon, provided habitat protection efforts are prioritized before further decline occurs.

This annual killifish inhabits temporary pools and seasonal wetlands in the Brazilian Cerrado savanna. The species depends on ephemeral water bodies that fill during the rainy season and dry completely during drought periods.