An African fish can grow from an egg to sexual maturity in just two weeks, earning it the title of the world’s fastest-maturing vertebrate.
The killifish spends most of its life as an embryo buried in the soil of the African savannah, but when the rains arrive and form pools of water the fish hatches and matures. Martin Reichard at the Czech Academy of Sciences in Brno and his colleagues collected turquoise killifish (Nothobranchius furzeri) from pools in Mozambique, estimating the age of each fish and examining the creatures to determine whether they were sexually mature. The team found that the wild killifish reached adulthood in as little as 14 days — even faster than times recorded for killifish reared in captivity.
This fast maturation ensures that the killifish has enough time to produce offspring, say the authors. Pools of rainwater that support fish populations dry up in as little as three weeks, leaving the fish just a short window in which to mate and deposit the eggs that will lie in the soil until the following year.