The Life Cycle of Fish

We thought we would walk you through the life cycle of a fish. Just to make sure you understand a bit more about these little creatures and the different stages they grow through before you get to harvest them as fully grown adults.

Fish Eggs

In the fish world, you get mouthbrooders and egg-layers. This refers to how the fish carry or lay their eggs. A mouthbrooder would hold the eggs in her mouth while waiting for them to hatch. During this period, they won’t eat so be careful not to overfeed. Some catfish and most tilapia are mouthbrooders. Trout lay their eggs on the bottom of the tank which means, they will continue to eat.

Fish Larvae

Stage two of the life cycle of a fish is the larvae stage. During this stage, the fish have a yolk sac that is attached to their body. This sac provides them with the required food for survival in these first few weeks of life.

Fish Fry

A fish is called a fry when they have consumed their yolk sac and they can finally eat by themselves. The fry are very small at this stage of life but they grow quickly.

Fingerlings

It’s all in the name, your fish are roughly the size of fingers at this stage in the life cycle. You’ll notice your fish forming scales and fins during this stage of growth. A lot of aquaponic farmers like to buy their fish at this stage in their life cycle as it is a lot easier to manage fish from this age onwards. When purchasing fish, we like to keep things above board. Check out our page on licences and permits required for purchasing fish in South Africa. Also, ensure you have calculated the correct stocking density when buying fingerlings.

Adult Fish

A fish becomes an adult when it becomes sexually functional. This is when you need to start considering harvesting your fish. This depends on the type of fish you are farming. You could wait longer for some fish to reach maturity than others. The type of fish also indicates what size fish you will be harvesting. Make sure you know the optimal time and weight to harvest your specific type of fish. These are all important points to consider when choosing your fish and calculating your possible income as a commercial farmer.

Fish can be finicky, so make sure you have researched how to properly care for them at each stage in their lifecycle. Check out our blog post: Common Fish in Aquaponics if you aren’t sure about what type of fish to farm in your system.