Fish food is the main input in an aquaponics system; therefore, it is essential to feed fish the right nutrition not only for the health of the fish but also because fish food becomes fish waste, which is the primary source of nutrients that feed the plants.
Thus, fish feed needs to fulfill both the fish and plants' nutritional requirements. It is important to fish feed with the best fish food in appropriate amounts to have a balanced and successful aquaponics system. But feeding your fish can be a challenge at first, especially if you are not sure your fish food meets their dietary requirements. This article discusses the fish food in aquaponics systems to serve as your guide to serving your fish the best fish food.
What do Aquaponics Fish Eat?
Different fish species require different diets. Some fish are herbivores, while others are carnivores and omnivores. Knowing the specific diet of your aquaponics fish is crucial to your system's health and success.
- Herbivore: Herbivorous fish eat only plant matter. Meaning fish species with this diet require feed that is high in fiber. Tilapia is an example of an herbivore, and they feed on algae and other aquatic plants in the wild. Herbivorous fish may like fruits and vegetables, duckweed, and algae in an aquaponics system.
- Carnivore: Carnivorous fish such as trout and barramundi require rich in protein fish food, which usually consists of meat (live or dead). Most carnivorous fish are predatory and eat smaller fish species. Carnivorous fish can be given critters, live fish, or brine shrimp.
- Omnivore: Omnivores are flexible eaters, meaning they can eat plants and meat. They are also easier to feed compared to other fish types.
Below is a list of common aquaponics fish and what they prefer to eat:
- Tilapia: This fish species is warm-water fish and omnivorous. The protein requirement for tilapia is 28-30%—tilapia feed on pellet or flakes, aquatic plants, duckweed, and vegetables.
- Perch: Perch prefers cool water and is adjustable to changes in the water's pH level. The protein requirement for perch is 36%. Perch are omnivorous fish species and feed on pellet or flakes, insects, and vegetables.
- Catfish:Catfish are sensitive to changes in water quality in the system, and the protein requirements are 25-55% depending on their age and size. This fish species is primarily omnivorous and feeds on pellets or flakes.
- Largemouth Bass: The protein requirement for bass is 40%. This fish species is omnivorous and feeds on pellet or flakes and smaller fish. Bass are sensitive to pH level changes, temperature, and changes in the water quality.
- Trout:Trout prefers cool water temperature and is also carnivorous. This fish species feeds on pellet or flakes and smaller fish. The protein requirement for trout is 37-41%.
- Carp: Carps are omnivorous and have nutrient requirements of 30-35%. They feed on pellets or flakes, insects, and aquatic plants.
- Goldfish and Koi: Goldfish and koi are ornamental fish and not suitable for eating. These fish feed on pellets or flakes, insects, and aquatic plants.
Almost every fish listed above will eat some variation of fish pellets. You can mix up your fish diets to follow their nutritional guidelines for optimal growth. Alternative fish food can also provide a good source of proteins, fats, and carbohydrates that pellets or flake offer.
Types of Aquaponics Fish Feed/Food
In choosing the best aquaponics fish food for your fish, you need to know if your fish is herbivorous, carnivorous, or omnivorous. As much as possible, try to mimic their feeding habits and food in the wild. The two types of aquaponics fish food are homemade fish food and commercial fish food.
Commercial Fish Food
Commercial pellets or flakes are the most practical choice for large-scale aquaponics systems and busy aquaponics growers. Commercial fish foods are ready to feed and formulated to meet your fish's dietary requirements. You can go for products that do not include GMO ingredients in purchasing commercial fish food, especially if you're planning to eat your fish. Keep in mind also to buy high-quality fish food that offers balanced nutrition.
Homemade Fish Food
Homemade fish foods are ideal for small aquaponics systems. Making your own fish food will ensure you have total control over what your fish eats and what goes into your system. If you decide to make your fish food, make sure you give the right balance of nutrients required for fish growth. Some of the homemade fish food is duckweed, insects, and vegetables.
Here is the list of aquaponics fish food:
Pellets or Flakes
Pellets and flakes are the most common fish food used in aquaponics. This is because they are packed with nutrients and have been specially made to deliver the nutrients required by the fish to grow healthy. The difference between pellets and flakes is:
- Pellets are fish food that sinks in the water. The advantage of using pellets is the fish can swallow its food naturally as they sink in the water. The disadvantage is that any leftover pellet needs to be removed from the water, as it may affect the system's water quality.
- Flakes float on the water, expecting the fish to come out and swallow them. The advantage of using flakes is they don't affect the water quality because they stay on the surface. The disadvantage is fish can gulp air while swallowing them, which can cause fish health problems.
Worms and Insects
You can grow your own worms and insects and use them to feed your fish. The types of worms and insects usually used in aquaponics systems are:
- Wingless flies
- Black soldier fly
- Blood worms
- Black worms
You can grow your own aquatic plants like duckweed, algae, water lettuce, azolla, etc. These aquatic plants can be grown easily by using a side stream system. To keep in mind, in growing these types of plants, they need to be monitored because they can clog your pumps.
Omnivorous fish species like tilapia and carp will eat vegetables like lettuce, peas, and other leftover vegetables from the garden. The best plant-based protein source for your fish is soy meal, cornmeal, and wheat.
Determining How Much to Feed Aquaponics Fish
Generally, fish fingerlings and above need to eat around 7% of their body weight per day in their youngest age and drop down to 4% of their body weight per day when nearing harvest age. Refer to the feeding chart to base your feeding on the specific fish you're raising. Adjust your feeding rates according to the average weight of a sample fish of at least 5-10 fish every two weeks to ensure you are not overfeeding or underfeeding your fish.
Feeding your fish with high-quality food is beneficial to the fish and the plants, especially if you plan to harvest fish for consumption. This is why it is essential to feed your fish with the best fish food suitable for their species. Commercial fish food is one of the easiest ways to feed your fish. However, it can also be expensive. So if you want to cut costs on your fish food, you can feed your fish with homemade fish food. Just make sure that the homemade fish food meets the nutritional requirements required by the fish and plants for healthy growth. Thank you for reading our article; read our full guide to fish feeding for more information on fish health in aquaponics.