2. Optimal tilapia farming conditions

The optimal conditions for farming tilapia, or any fish for that matter, are complex and sophisticated. The recipe for production of tilapia is different to that of catfish or carp or salmon. Even between different species of tilapia the formula for optimum conditions can vary.

You need to focus on providing the tilapia with optimum conditions for the sole reason that you want them to grow as rapidly as possible. In the previous page we have seen that production depends on the rate of growth of the fish and the final harvest size. If you have control over both of these factors you have control over your production.

Tilapia are warm water fish. They grow optimally at 28C. At 26C the growth rate is 30% less than at 28C. At 22C they do not grow at all. Temperature is the biggest influencer on growth rates. If you do not have the optimum temperature all other factors fall by the way side and you can provide the fish with pristine, perfect conditions and your growth rates will not be what they need to be.

Oxygen levels need to be above 5mg/l. If these can be maintained higher stocking densities can be accommodated. Higher stocking densities mean greater production from the same body of water. However, oxygen levels are affected by water temperature – the higher the temperature the less oxygen dissolves into water. Also atmospheric pressure influences dissolved oxygen levels – at altitude in Gauteng (1400m above sea level) we have a lower atmospheric pressure and less oxygen can dissolve into water.

If your oxygen levels drop below 5mg/l the fish will slow their growth rates. Stress will be placed on them and this can trigger disease.

Tilapia need good quality feed. Although vegetarian in nature they are in fact natural filter feeders that live off algae and other plant material primarily. A good quality pelletised diet is necessary to ensure optimum growth levels.

Lastly tilapia need good water quality. This in itself is a complex topic.

The point you need to understand is that just in these four broad areas of influence it is possible to conjure up hundreds of differing combinations of these four, all of which influence the growth rate of fish. The inter relationships between them further complicates matter – the relationship between oxygen and water temperature is an example. Too much heat can be a bad thing.

The relationship between feed and oxygen also needs to be taken into account. Feed affects water quality which in turn can affect oxygen levels.

It is not a stretch to pass the comment that everything influences everything else when it comes to aquaculture. It can be very easy indeed to overlook a key relationship that in turn influences the growth rate of your fish, and it can spell financial ruin. Many aspirant aquaculturists have learned this the hard way, many with ‘expert’ advice on board.