There are a number of factors that help determine the types of fish used in aquaponics gardening. These include cost, how much maintenance you are willing to do and the climate you live in. The cost of the fish you choose will depend on where you live and availability of the fish you wish stock your fish rearing tanks with. Maintenance depends on the level of cleanliness the fish needs in the water for them to thrive. These factors you can control. However the climate you live in cannot. If you choose to stock your fish rearing tanks with fish that need warm water, you will have to heat the water if you want them to grow or even survive. You cannot control the climate, but you can heat the water. This however will come at a cost.
The tilapia fish is commonly used in aquaponics gardening. It is of the edible variety and is a good source of protein. The tilapia breeds quickly and can tolerate high stocking densities. This means it can be harvested a number of times per year and still provide the needed nutrients to the plants in your grow beds. However they do have some drawbacks. This has to do with climate. The tilapia requires water temperatures in the range of 28 to 30 degrees Celsius to thrive in. When the water temperature drops down to 20 degrees celsius the fish will stop growing. If the water temperature goes down to 10 degrees celsius, they will start to die. If you live in a cold climate you will have to heat the water and this will cost you money. You will have to include water heaters in your list of aquaponics supplies to purchase and pay more for electricity. In this case you will be better off stocking your fish tanks with a fish better suited to living in cold water such as trout if you do not want to pay the extra money.
Trout are commonly used by aquaponics farmers in cold climates, especially during the winter months. However because the water in your aquaponics garden with be cold, the types of plants you will be able to successfully grow will be limited. Most plants need warm water to grow properly in an aquaponics garden.
Unlike tilapia, trout are rather picky about the cleanliness of water. Trout need pristine water to live in. When stocking your fish rearing tanks with trout you need to pay special attention to the cleanliness of the water. This will also involve purchasing equipment that will help keep the water in a pristine state.
There are a number resources on the internet that will provide you with information about choosing the correct aquaponics fish for your location. Some of these resources are free and others will require payment. Often the resources that require payment provide better quality information and are worth the investment in the long run.