Fertilized eggs are retained and develop within the female's ovary or uterus. The developing embryo has a nutrient connection with the mother. E. Release of offspring. There is great variation in the development stage at which offspring are released. Depending on whether fertilization is internal or external and which type of embryonic development occurs, bony fishes may release eggs or sperm, larvae, or even sexually mature adult fishes.
Gestation periods vary among species and between individuals within a species.
Since bony fishes are cold-blooded, gestation time may vary within a species. The rate at which the embryo develops depends on the water temperature. The gestation period may be as short as a few days or as long as several months. The number of offspring is inversely related to the chance a single egg has to reach maturity and reproduce. In general, species whose eggs have little chance to reach maturity lay the most eggs.