Tilapia were our fish of choice for our larger aquaponic system. Not only do they taste good they are pretty easy to look after and are a hardy fish that can withstand a drop in ideal water parameters. Before keeping them however, there are some important basics to get to know.
Temperature: Tilapia require heated water, especially here in the UK! 28°C is the ideal temperature and this can be achieved with an ordinary aquarium heater that is the right size for your tank. A few degrees either way probably won’t make much difference but they definitely cannot stand extended periods of colder water.
Oxygen: Water dropping from the grow bed into the fish tank will agitate the water surface and allow for an exchange of gases, oxygenating the water. It is a good idea to add an extra air stone incase your system is on a timer and the water goes still for long period of time. If you spot any fish gasping at the surface definitely try adding another air stone. Tilapia also use oxygen to metabolise their food making the need for an air pump even more important.
Feeding: It’s always best to get a good quality feed especially made for tilapia. It’s also possible to feed them directly from your system, or incorporate growing something like duckweed that be fed straight to the fish. Tilapia can be mostly vegetarian although in their earlier development they need a lot more protein. Feeding smaller amounts spread throughout the day will be easier on the system and more regular for the fish. We are using an automatic feeder for when we aren’t around to make sure they get their feed. We are feeding 3 to 4 times per day and only what they can eat in a few minutes, if there is food being left by the fish cut back on the food per feeding. Amount of food to be given will change as the tilapia grow, it’s important not to underfeed them!
Stocking Density: Without going into specifics of gram per cubic foot, a general answer is one adult tilapia per 10 litres. We have taken this rule as the absolute maximum and have stocked under this amount.
Water Parameters: While I mentioned tilapia being a hardy fish this is no excuse to keep slack water parameters! It just means if there is a slip up or a pump stops working there is some leeway to fixing to problem. Ammonia and nitrite should be at 0 ppm to keep the fish in optimum health. Nitrate should be kept under control with regular testing to make sure the plants are doing their job and taking this from the water.
Sourcing: Our tilapia have come from Fish Farm UK based in Bow. They deliver to other places in the UK and we highly recommend them. Most sizes are available at a reasonable rate and they care about their fish! A quick online search will provide other suppliers.