Tilapia has been cultured in ponds for thousands of years in its native African and Middle East, while the practise of using tanks or cages instead of ponds is a 20th century invention. Tank culturing of tilapia is quite common in regions where suitable land for tilapia cultivation is scarce or there is a shortage of inexpensive water. Compared to pond farming of tilapia the stocking density is usually very high in tanks.
A densely stocked tilapia tank needs to be meticulously controlled when it comes to water quality and oxygen levels because even a small shift in the wrong direction can cause mass deaths or epidemics. Waste products must be removed continuously and oxygen must be added. This is usually achieved through frequent or continuous water changes, with some tank systems recycling the water and others discarding it in favour of new water. A flow-through system will rely on constant access to new, fresh water while a recirculation system or recirculating system clean the used water and reuse it over and over again.
Which system that is best for a tilapia tank farm depends on several factors, including climate and access to water. Outside the tropics, water must be heated if you want to be able to produce tilapia year round and the cost of discarding heated water and warming up new is usually very high.Recirculation systems are therefore a sound investment in most situations and both tanks and water systems tend to be placed inside insulated buildings. In the tropics where the water does not have to be heated, flow-through systems are more common. You can also see flow-through systems in parts of the world where fish farmers have access to geothermal water or other types of inexpensive hot water. In the future, we might se more and more tilapia farms utilizing surplus hot water from power plants.
The recommended water temperature for most tilapia species, hybrids and variants is 28-30 degrees C (82-86 degrees F). If the temperature drops below 20 degrees C (50 degrees F) you will see a dramatic decline in growth rate, but the fish can usually survive drops down to 10 degrees C (50 degrees F). It is however important to keep in mind that even though your fish might survive below the recommended temperature range the suboptimal temperature will affect its immune system making it more susceptible to poor health. This becomes especially noticeable around 13 degrees C (55 degrees F); a temperature that rarely kills tilapia instantly but makes them very prone to illness.
Which tilapia species, hybrid or strain that is the best choice for your particular tank depends on several different factors and it is impossible to make any suggestions without knowing more about the environment in which they will be raised. Blue tilapia (Oreochromis aureus) will for instance grow fairly slow, but is remarkably cold tolerant and therefore a good choice in cooler waters. The Nile tilapia (Oreochromis niloticus) will grow much faster than its blue relative, but requires tropical conditions to retain its health and swift growth rate. In addition to the species, many different hybrids and strains have been developed for tilapia culture; some specially adapted to life in tanks.
Last but not least, some countries and states have banned certain types of tilapia so make sure you check local regulations before you make any purchase.