Small-scale or new aquaponics systems can typically do just fine using commerical feed pellets, as long as they provide enough nutrients to power your system. There are alternative options however, which can be great ways to lower your overall costs by reducing your fish feed budget. Some of these options include duckweed, insects, or even smaller fish. Duckweed is a small aquatic plant that grows very quickly in nutrient-rich water, like that in your aquaponics system. This plant helps create a healthy environment for your fish by utilizing any excess nutrients within the tank, like phosphorous or nitrogen. Insects are rich in proteins and amino acids, and are powerful sources of protein for carnivorous fish. Crickets, insect larvae, fish eggs, worms, and cockroaches are all popular choices for aquaponics farmers.
Your fish need several primary nutrients in order to thrive. These include protein, fish oil, carbohydrates, lipids, and vitamins and minerals. Young fish, or carnivorous fish, will need higher protein diets. Carnivores like trout and bass would prefer a diet somewhere in the range of 40-50% protein. Omnivorous fish like tilapia, koi, or catfish require less protein, around 32%. Ensuring that your fish are getting the right nutrients means that they'll be able to provide your plants everything they'll need to grow.
