Golden Freshwater Clam

Pond Culture of Tilapia

Tilapia is a popular food fish that has been aquacultured for thousands of years. The Ancient Egyptians are believed to have been the first to farm tilapia in ponds. Today, tilapia is also raised in tanks and cages. Pond raising, tank raising and cage raising all have their own pros and cons and it is important to carefully assess the situation before you make any decisions.

Pond culture is still the most commonly used method of raising tilapia. One of the big advantages with a pond culture is that is closely resembles the life of wild tilapia and makes it possible for the fish to feed on naturally occurring food. Unfortunately, tilapia loves to spawn in ponds and the number of fry and fingerlings can rapidly reach large quantities if male and female fish are kept together. This will result in a situation where fry and fingerlings compete for food with the adults, resulting in a lower growth speed for the fish in the pond. One way of solving the problem is to cultivate male fish only in the pond. Ponds also tend to become a part of the natural landscape, for good and for bad. When animals such as birds and snails are attracted to the pond, they can bring parasites that cause trouble for tilapia.

Choosing species

The perfect species for your pond will depend on your particular circumstances and goals. Also keep in mind that tilapia hybrids can be a great alternative to pure species. Generally speaking, mouth brooding species and hybrids are used to produce fish for the food market, while substrate spawners are the primary choice for weed control. 

In the United States, four of the most commonly grown food tilapias are Nile tilapia (Oreochromis niloticus), Mozambique Tilapia (Oreochromis mossambicus), Blue tilapia (Oreochromis aureus ) and Wami tilapia (Oreochromis urolepis hornorum). Nile tilapia and Blue tilapia are known to have the highest growth rate in ponds, but Nile tilapia is normally less cold tolerant than Blue tilapia.

The pond

Tilapia can be grown in virtually any type of pond, but most farmers prefer small and fairly shallow ponds since they are easier to drain when its time for harvest. Installing drains is recommended, since harvesting using seines only is very difficult. It is also common among fish farmers to let the bottom of the pond dry out before the new fish arrives, in order to kill off any fry and fingerlings that might otherwise interfere with the new production cycle.

If you live outside the tropics, you must be able to heat the water during the cold season unless you want production to stop. The recommended water temperature year round is 28-30 degrees C (82-86 degrees F). A dramatically lowered growth rate can be seen as soon as the temperature drops below 20 degrees C (68 degrees F). Deaths can start occurring when the water temperature drops below 10 degrees C (50 degrees F) depending on tilapia species, and temperatures below 13 degrees F (55 degrees F) are harmful to the immune system of the fish.

Farming tilapia with other species

There are several reasons why combing tilapia with other species can be a good idea. More than one species normally means that even more of the natural food in the pond can be used, as long as you combine species that utilize different food niches. Combining several species can also lead to improved water quality thanks to more well balanced communities of micro organisms. Last but not least, species can be introduced to control the amount of tilapia offspring in a pond where both male and female tilapia is present. If you are interested in introducing new species to the pond, you should keep in mind that you might have to invest in sorting devices and other types of special equipment.  

Tilapia can be grown together with a wide range of other animals, such as channel catfish (Ictalurus punctatus) and the prawn Macrobrachium rosenbergii. You must naturally stick to species that are legal in your part of the world. If you want to reduce the amount of tilapia fry and fingerlings in your growing unit, you can use predatory fish species like largemouth bass (Micropterus salmoides), peacock bass (Cichla ocellaris) and guapote tigre (Cichlasoma managuense). It is important to choose small predatory fish; otherwise they might attack the adult tilapias.

Feeding tilapia

Proving your tilapia with a proper diet is very important if you want to obtain optimal growth results and boost the immune system of your fish. Many of the most commonly cultivated species feed on plankton and detritus in the wild and are therefore not very expensive to feed in a pond. It is common among tilapia farmers to increase the natural production of plankton and detritus in the pond by adding fertilizers and/or manure. For really high yields, supplemental feedings are normally required. If you are okay with a somewhat lower yield, fertilizers and manure is often enough in a well functioning pond.  

When it comes to fertilizers, it is important to keep in mind that tilapia productivity is stimulated chiefly by phosphorus material and only to a lesser extent by nitrogenous compounds. Many fish farmers are hesitant to use inorganic fertilizers since they tend to be quite costly, but doing one large application of phosphorus rich inorganic fertilizer before you stock the pond with fish can be worth the extra cost since it will increase the chances of an algal bloom.

Adding manure to the pond is another method for fish farmers that wish to increase the productivity of the pond. It is fairly uncommon in the United States, but widely used many other parts of the world. The manure producing animals are often located near the fish ponds to save money and effort on storage and transportation. Fresh manure can then easily be added to the pond on a regular basis.

Generally speaking, manure from chickens, ducks and pigs will increase production more than manure from cows and sheep. The choice of animal is however not the only factor that will effect the quality of the manure; using manure from animals that have been fed high quality food, e.g. mostly grains instead of mostly crude fibre, is also recommended.

It is important not to add too much manure, because too much manure will lead to reduced levels of dissolved oxygen in the water. The maximal recommended amount depends on several factors, including water temperature, current oxygen supply in the water and the quality of the manure. Fish size and stocking density much also be taken into account.

Using manure when the water temperature is below 18 degrees C (64 degrees F) can be hazardous, since a low temperature will decrease the decomposition rate in the pond. Without speedy decomposition, the manure will gather on the bottom of the pond instead of decomposing. When the water becomes warm again, the accumulated manure can cause a sharp decline in dissolved oxygen. It is also safest never to use manure when the amount of dissolved oxygen is below 2 ppm when measured early in the morning.

The most commonly used method of dispersal is to spread manure evenly over the surface of the pond. Dumping manure in a few spots is less labour intensive, but large piles of manure can easily result in oxygen scarcity in the sediment. This will make life harder for beneficial micro organisms that needs oxygen for their activities, and it can also lead to sudden outbursts of toxic chemicals. If you have a choice, spreading fresh manure is better than dry manure in most cases. It is also best to use finely divided manure since large clumps of manure have a much smaller combined surface area than a myriad of small clomps. Surface area is important since it will be colonised by micro organisms.

Harvesting tilapia from the pond

One of the most commonly used methods for harvesting pond grown tilapia involves both seining and draining of the pond. It is hard to catch all the tilapias using only seining since theses fishes are skilled escape artists.