The Julimes pupfish (Cyprinodon julimes) (Spanish: Cachorrito de Julimes), is a killifish belonging to the family Cyprinodontidae (pupfish) of ray-finned fish, endemic to "El Pandeño" hot spring in Julimes, Chihuahua, Mexico. The pupfish is known as the "hottest fish in the world" due to its adaptation to life in a hot spring that reaches temperatures as high as 114 °F (46 °C). The species was taxonomically described in 2009 as similar to Cyprinodon eximius, but it has a bigger head, nearly one-third of its Standard Length.