Guide to Fish in Aquaponics Systems
Who doesn’t love fish? Gaylen and Helen sure do. Gaylen wants his fish aquaponics system fully integrated with new fish to satisfy his appetite for fresh fish. If you’ve been looking for information about how to add fish in a newly established aquaponics system, chances are, you are a full-blooded fish eater.
You have a good appetite for healthy, fresh fish and that’s probably one of the reasons why you want an aquaponics system in your backyard in the first place.
As Helen and Gaylen know, a successful aquaponics system is dependent on three main components: fish, bacteria, and plants. Without the fish, your organic vegetables will not survive. And without the plants, the fish will die off quickly because the water will become toxic with nitrates, ammonia, and other waste products.
Without bacteria, Helen knows the plants would not be able to absorb vital nitrates from the water. So each component is important to the system. Remove one component, and the system will fall apart.
Gaylen is Focusing on the Fish
Tilapia is easily the best choice for aquaponics systems, regardless of the size of the setup. If you live in a relatively warm place in the United States, you can consult with your local agriculture bureau to find out if you can raise tilapia in your backyard aquaponics system.
If tilapia is not a good choice, you have can also raise a variety of other freshwater fish such as koi fish and crappie fish. Most common edible freshwater fish can be used in aquaponics systems.
Some people even breed bass in their backyards. We recommend tilapia because these fish grow very quickly and are one of the hardiest groups of edible fish around. Tilapias are cichlids and are usually found in the tropics.
As for how many fish to raise in your holding tank, it really depends on how much space you have and the type of filtration system you’ve installed in your tank. Small-scale commercial producers usually add half a pound of fish for every one gallon of water in their tank.
The number of fish also has a bearing on how much vegetation your aquaponics system can support. Three factors come into play when it comes to determining how much vegetation your fish can support (indirectly):
– The volume of fish you have in the tank
– The maturation, weight, and size of the fish
– How much food is being added to the holding tank on a daily basis
If you are utilizing a simple raft setup (elevated growing beds), one square meter of growing vegetation will require at least sixty grams of fish food on a daily basis.
If you are taking care of more demanding vegetables such as squash, you need at least one hundred grams of fish food every day. Remember, your plants will be completely dependent on the waste products of the fish and the excess fish feed in the water.
If there is insufficient fish waste, the vegetables will have no way to grow because the water will have very minimal levels of organic matter and usable nitrates.
Inversely, if you add too much food to the holding tanks, you run the risk of poisoning the fish because too much food directly translates to excess waste in the water. You have to find the balance that will sustain both the fish and your aquaponic vegetables/fruits.