In this post we will go over what to feed your fish, and how many fish you should have in the tank in relation to the size of your Aquaponics system.
Aquaponics Fish Food
Keeping track of the aquaponics fish food you are applying is one of the more important routines you will do for your system’s environment. Since the fish supply the waste that the plants need, you need to make sure they are fed consistently.
Plan a schedule for how often you will feed your fish. Over feeding them can pollute the water as well as the rest of the system. Monitor the tank frequently and be sure to clean the water as needed. If they are not eating all of the food you apply you need to remove it and consider feeding them less quantity until they are eating all that you supply.
Fish tend to eat 1.5 percent of their body weight every day. You can use this ratio to help you decide how much to give them, taking into consideration whether they are full grown or little fingerlings.
Another thing to consider is the quality of the food you are feeding them. Toxins in the food will tricle down to the plants and the vegetables that you are going to eat.
You’ll need to determine whether the fish you have are primarily plant food eaters, or omnivorous. Either way, all fish need carbohydrates, protein, and fats just like us. When you’ve decided which food types are best for your fish, choose between store-bought pellets, growing the food yourself, or both.
DIY Fish Food For Aquaponics
If you are so inclined, you can find or make your own aquaponics fish food. For protein, you can find insects and worms or grow them yourself. Omnivorous fish in the wild will go after crickets, insect larvae, flies, tiny crustaceans, cockroaches, fish eggs, and all types of worms like blackworms, earthworms, and Red wigglers.
For fish that are primarily plant feeders you can grow their food in your aquaponics trays. Duckweed is very popular and contains 30% to 40% protein as well as other nutrients. Water lettuce, and elodea can also be grown easily in your aquaponics grow beds, just be sure to dry them off before feeding.
Another plant that is even higher in protein is the algae, Spirulina. This is the same algae that is sold in health food stores known for its protein as well as vitamins and minerals, manganese, zinc, selinium and more. Spirulina will only live in warm temperatures so it would be best to grow it in small heated aquariums.
Fish also love many fruits and veggies that you may have in your own aquaponics garden. Among these are kale, lettuce, watercress and even apples and grapes.
If you are harvesting edible fish consider using only USDA certified Organic and Non-GMO food products. This is not only for the well-being of the fish, but also for your own health when you put them on your menu.
Pellet Fish Food
Aquaponics Pellet fish food comes in a variety of brands often specific to types of fish ie., ornamental, omnivorous, vegetarians, large fish and small. A few things to keep in mind:
Make sure it’s a floating pellet and are preferrable no bigger that 1/8 inch in size
Roughly 30% protein, at least 6% fat, and with healthy by-products
Don’t go for cheap deal fish foods wish can result in poor quality waste poops that can be toxic to the plants and those that eat them.
Most Tilapia are farm raised and fed GMO Soy and corn pellets that are unhealthy for them and those of us that eat Tilapia. In the wild they prefer a menu of water plants like algae and duckweed also known as Duck Wheat) which has a high protein content.
You can grow the algae and duckweed yourself for Tilapia fish food. In ponds Duckweed can grow so fast that it blocks other plants from sunlight, but that won’t be an issue in your aquaponics grow beds. Just be sure to isolate them in separate trays from other plant types.
Since they won’t eat smaller fish they they don’t get caught up in the mercury content that omnivors do. Their mercury content is much lower which means they are a much healthier for usas a food to consume.
Ever thought of making your own Tilapia aquaponics fish food? Here is a fairly easy recipe you can try yourself.
- 1. Put some leafy greens like kale, swiss chard, and lettuce in a food processor then add some veggie roots like turnups and seaweed if available- now blend it into a puree
- 2. Add some protein like fish meal, Duckweed, or Spirulina and blend a little more.
- 3. Keep blending until smooth while adding liquid of your choice be it water, lemon juice, or vegetable juice. The object is to build a dough type of texture
- 4. Now you can ad some grinded-down vitamins and fish oil keeping the dough-like consistancy
- 5. Now run the through a Pasta Rolling Machine or Meat grinder. When you see the noodles appear out the other side of the tool, cut them into pellet-size pieces with a sharp blade
- 6. Now you will put the pellets on a sheet of foil and dehydrate them at a low temperature in your oven while occasionally spraying them with olive oil.
- 7. When the pellets have dried off thoroughly you can enclose them in freezer bags where they can stay fresh for up to six months
Here is an article for more information on making your own pellets Fish Food Pellets
Other Aquaponics Fish Food Types
Here is a list of typical Aquaponics fish you may have and what they prefer to eat in the wild. Most of these are plants, insects, and aqua animals that you can find, grow, or purchase alive or as fish food products such as pellets.
Trout Aquaponics Food
Strictly carnivorous that won’t eat plants and will consume:
- smaller fish-minnows and other local fry fish (fish that have developed enough to feed themselves)
- aquatic insects-mayflies, water fleas, etc
- worms and leaches
- salmon eggs
Similar to the Trout these are carnivorous. As fry’s they will eat small insects, then at full grown become predators of other fish.
- insect larvae
- small aquatic birds (ie. newborn ducklings)
- water plants- duckweed, algaes, etc
- fly larvae and small bugs
- Fry fish
- many types of worms
Ornamental Koi Fish
Koi Fish are omnivorous and will eat just about anything. This Includes:
- small insects
- Many fruits like watermelon, apples, etc.
- Lettuce, Kale and Spinach, peas
- Fingerling fish and shrimp
- water plants particularly bottom feeders
- flies and other incects larvae
- water insects like water beetles
- small fish at maturity
- dragonfly’s and their larvae
- crawfish and snails
Bluegills and Crappies
- small fry fish
- aquatic insects
How Many Fish For The Aquaponics System
To determine how many fish to keep in your tank, a general rule of thumb is to have one fish for every 5 gallons of fish tank capacity. This is going to vary quite a bit depending on the age and weight of the fish.
Another way of determining how many fish to start with, consider the amount of grow bed media you are using, rather than the gallons of water in your aquaponics fish tank.
Since Hydroton is the preferred media we will use it as an example. You should have a minimum of 3.3 gallons of growbed container capacity filled with Hydroton for every pound of fish that are fully grown. At the same time, if you plan on 3 gallons of water in the fish tank for every pound of fish, this will workout to 1 gallon of grow bed container quantity to 1 gallon of fish tank capacity.
This might seem a bit complicated so if you want to start out with the first option, just be sure to keep an eye on the fish waste. Don’t allow it to accumulate and clog up the system. If you’re using the grow media as a bio-filter, make adjustments to the amount of fish you keep and how much food you’re feeding them until the water is consistently clean.
If you’re new to Aquaponics, I would recommend beginning with a 1:1 ratio of aquaponics tank capacity to media grow bed container. This way your tank will have acceptable filtration because your fish tank volume is the same as the volume of the grow bed.
As your System matures you can increase the ratio to 2:1 as your fish get bigger. At this point you may even want to add more grow beds and use a separate filtration device. This will enable more filtration in your system which is better for your fish’s long term health. Just be sure to continue monitoring the system and maintaining the ratio balance between the fish tank and the grow beds .
Finding the balance between all of these components is the key to having a productive and healthy Aquaponics System. How much money will you save from buying food at the market with your Aquaponics system? The answer depends on the size of your system, and how well you stick to the principals of Aquaponics system maintenance. In order to create a successful aquaponics system, you must understand the ideal ratios between the grow bed and the fish tank.