Some fish eggs can hatch within three days of being laid, while others can take as long as 14 days. The length of time it takes a fish egg to hatch depends on many factors, including the species of fish and environmental conditions.
Most marine fish produce thousands of eggs per spawning event. A fish typically puts her eggs into the water to be fertilized, or the fish may make a nest for her eggs. Fish eggs begin to mature rapidly after fertilization, but egg mortality is quite high. Predators eat the majority of the eggs laid in the water. Water temperature and oxygen levels in the water also influence egg mortality.