Tiny African Fish have Most Rapid Sexual Maturation of Any Vertebrate Species on Earth

Researchers have discovered that tiny African annual fish have the most rapid sexual maturation of any vertebrate species on Earth.

Call it a feat of evolutionary and environmental necessity. The African annual fish makes their home in seasonal puddles; the fish need to reach sexual maturity fast enough to reproduce before the temporary puddles created by seasonal rainfall evaporate.

By studying wild-caught African annual fish in captivity, researchers, led by Martin Reichard, an ichthyologist at the Academy of Sciences of the Czech Republic, learned that the fish can grow up to 23 percent of their body length in just one day.

"One species, Nothobranchius kadleci started reproducing at 17 days old, at a size of just 31 mm, with a related species, N. furzeri maturing only one day later," the researchers wrote in a news release. "The fish then produced eggs that developed to the hatching stage in as few as 15 days, making the time from one generation to the next as little as month -- the most rapid sexual maturation time and minimum generation time of any known vertebrate species."

These annual fish are mainly found in East Africa from Sudan to northern South Africa. N. furzeri, for instance, typically live between three and six months, hatching, breeding and dying in just a short time.

While these African annual fish give credence to the phrase "live fast, die young," other animals that enjoy longer lifespans are able to take life at a much more leisurely pace. The tiny cave-dwelling salamander Proteus anguinus, for instance, lives more than 100 years and takes 16 years to reach sexual maturity.

Because of their short lifespans, the African annual fish such as the N. furzeri are attractive models for ageing research.

Reichard and his colleagues' research is published in the open-access journal EvoDevo as part of a series on extreme environments.