Embryology
Mosquitofish have a 16 to 28 day gestation period. Mosquitofish are lecithotrophic, which means during gestation, nutrients are provided to the embryos by a yolk sac. If the gestation period is shorter, each newborn will at birth still have a yolk sac connected through a slit located on the ventral side of the body wall. Brood size of females depends on the size of the given female; larger females are more capable of a larger brood quantity than smaller females. Most females, though, have a brood quantity of about 60 young. Mosquitofish are viviparous, which means after the gestation of a brood, the female will have live birth. In most cases, the newborn brood will have an equal male to female ratio.
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