How Do Fish Lay Eggs?

Some fish eggs are considered human delicacies.

How Fish Lay Eggs

Fish lay eggs instead of giving birth to live young, and the eggs hatch into "fry" with a yolk sac still attached to them. After about a week to 10 days in this form, the fry mature into fish.
Fish lay their eggs in different ways. Some female fish scatter their eggs around the tank or pond while the male fertilizes them. Other females attach their eggs to something like a piece of wood or even the glass of the aquarium, and the male fertilizes the eggs as she lays them. Some fish even carry their eggs in their mouths once the female lays them and the male fertilizes them.

Different Kinds of Egg-Laying Fish

Some fish, called egg scatters, put their eggs in different places in weeds or gravel. As the female is laying the eggs, the male chases her around and fertilizes the eggs. If you are lucky enough to see this process, you may be amazed because the fish don't pay attention to anything else, even food! Tetras and barbs are examples of egg scatters.
Substrate spawners, such as catfish or cichlids, put their eggs on plants, a piece of wood or the tank until they hatch.
A very interesting type of fish are the bubblenest builders. They actually build a nest for their eggs in bubbles that the male blows. The bubbles look like foam and are held together by saliva.
Finally, mouthbrooders keep their eggs in their mouths until after they hatch. Both the male and the female may carry the eggs, and the carrier does not eat very much until the eggs hatch.

Problems to Watch Out For

Some people complain that their male and female fish eat the fish eggs before they hatch. Different types of fish act differently after laying eggs. Some, such as bubblenest builders and mouthbrooders, have one parent that guards the eggs from other fish. Cichlids have both parents guard the eggs and the young. If you are having trouble with your fish eating the eggs, or your fish are being aggressive with one another, you can set up a separate breeding tank. Once the fish lay eggs, you can remove them from the tank and put them in another.