For example, guppies, a type of livebearer, give birth to live young after a gestation period of about 28 days. On the other hand, some species of clownfish can take up to two or three months to hatch after fertilization of the eggs has taken place.
Environmental factors, such as water temperature and the presence of predators, can affect the incubation period of fish eggs. Generally, warmer water temperatures speed up the development of fish embryos, leading to shorter incubation periods.