A stunning new species of killifish, Nothobranchius sylvaticus, was discovered in Kenya's Gongoni Forest in December 2025. What type of habitat is this the first known killifish to live in?

The recent discovery of *Nothobranchius sylvaticus* in Kenya's Gongoni Forest marks a significant moment in ichthyology, as this species is the first known killifish to inhabit a forest environment. The very name *sylvaticus* is Latin for "pertaining to the forest," directly acknowledging its unique dwelling. Found in seasonal swamps within this ancient ecosystem, this vibrant fish, with its iridescent blue scales and striking red markings, challenges previous understandings of killifish habitats.

Killifish, a diverse group of over 1,270 species, are typically found in tropical and subtropical waters across various continents, excluding Australia and Antarctica. Their usual homes include temporary pools, swamps, creeks, and shallow streams, with some species even adapting to brackish estuary habitats. Many are known for their remarkable "annual" life cycle, where they live, reproduce, and die within a single wet season, with their eggs capable of surviving dormant in the dried mud until the next rains.

The Gongoni Forest, where *Nothobranchius sylvaticus* was discovered, is an ancient and relict forest, estimated to be over 7.1 million years old. This makes the discovery not only a revelation about killifish adaptability but also highlights the ecological importance of such unique, isolated forest patches. Unfortunately, this new species is already classified as critically endangered due to its severely restricted and declining habitat, emphasizing the urgent need for conservation efforts to protect this forest-dwelling killifish and its rare home.