Pelos vistos tenho de requisitar um Gervásio para aqui...
From WIKIPEDIA:
killifish is any of various oviparous (egg-laying) cyprinodontiform fish (including families Aplocheilidae, Cyprinodontidae, Fundulidae, Nothobranchiidae, Profundulidae, Rivulidae and Valenciidae). All in all there are some 1270 different species of killifish, the biggest family being Rivulidae, containing more than 320 species.[1] Although killifish is sometimes used as an English equivalent to Cyprinodontidae, some species belonging to that family have their own common names, such as the pupfish and the mummichog. The name killifish is derived from the Dutch word "kilde", meaning small creek, puddle. Most killies are small fish, from one to two inches (2.5 to 5 cm), with the largest species growing to just under six inches (15 cm).
Ou seja, Killis são cprinodontideos (ou lá como se escreve). Pertencem à familia das carpas dentadas e são originarios de todo o Mundo e vivem em correntes e pequenas poças.
Até em Portugal há killis.
Como vê meu caro, a informação está disponível, basta perder um nadinha e procurar