Diadromous fishes must have access to both marine and freshwater systems to complete their life cycle. D. Embryonic development. In oviparous development, the female releases eggs. The developing embryo is nourished by a yolk sac. Bony fish eggs generally are spherical.
Some bony fishes lay eggs that drift through the water column.
Some bony fish eggs have oil droplets that help them float. Some eggs may be sticky or may have tendrils that allow them to attach to plants and other living or nonliving materials in the environment. Some species brood eggs in their mouth or on their skin, fins, or gill areas. Some fishes that have internal fertilization are ovoviviparous. The female retains fertilized eggs in her body.