The ponds to be stocked must be prepared adequately before stocking.
Preparation of new pond for stocking
- Final finishing (for new ponds), removal of mud and repairs (old ponds)
- Liming the pond
- Fixing pipes and screens
- Fertilising the pond
- Filling the pond with water
- Allowing time for the pond to turn green
The pipe to let water into the pond (inlet pipes) is fixed at the shallowest point of the pond. And the drainage pipe is fixed at the deepest end of the pond.
The inlet pipes must be screened to keep away wild fish from entering the pond. A netting material with very fine mesh is used.
The pond is fertilized first before filling with water
Pond fertilization is done to allow growth of natural foods for the fry to be stocked. If fry is stocked before building up the quantity of natural foods, the fry may starve or grow slowly and become stunted.
Several materials can be used for fertilizing ponds, including agricultural (also called inorganic) fertilizers and manure (called organic fertilizers).
1.0 Agricultural or inorganic fertilizers
These include: NPK, TSP, SSP, Urea. All these are in powder or granular form. They are available in shops selling Agricultural chemical. Details are given in Section 4
2. Organic fertilizers (manure)
The sources of manure include chicken dropping and urine
- Cow dung and urine
- Pig dung and urine
- Sunflower cake
When the pond has developed these organisms (algae) turned green, it is ready for stocking
If fry is stocked before sufficient food has grown in the pond, the fry will not grow well.
Preparation of pond that previously had fish
For the pond in which fish have already been grown, there is no need to go through the whole long process required for the new pond. The important points are:-
- To completely drain the pond, remove all the fish (fry or eggs) that may have remained from the previous
- To kill off all the germs and other animals that may be at the pond bottom (eg tad poles, frog eggs, insects, etc)
- To allow the pond to completely dry up so that the mud breaks up)
After drying the pond, it may require some repair work before it is ready fro re-stocking.
Removing the bottom mud.
Mud accumulated in the pond comes from two sources:
- Banks that keep collapsing and falling into the pond, and
- The remains of manure and other feeds that were given to fish and the feces that fish produce.
It is important to remove the mud because it reduces the productivity of the pond. It may also be prone to disease. After allowing it to dry the mud becomes lighter and easier to remove. It is simply scraped from the bond bottom using hoes or shovels
The lighter surface mud, rich in manure, should be carried away and used to fertilize gardens.
The more firm mud should be used to build back the pond dyke that has collapsed or is in danger of collapse.
A used pond may require some repair as a result of:-
- The banks collapsing to the bottom and accumulating as mud
- Some fish that dig up the pond banks and dykes, causing leakages
- Roots of trees growing bigger and causing cracks through pond dykes
Pond repairs therefore, include:
- Building back the collapsed pond banks and re-shaping the pond using the firm soils from the
- Sealing off any leakages
After all these repairs the pond is prepared for stocking. The process follows the steps outlined as for new ponds: Liming, fertilizing, fixing inlets and outlets and filling the pond with water.
In case of used ponds, however, the lime also helps to kill off germs and eggs or fry from previous harvests.
The pond is filled with water through the inlet pipes. The screens prevent entry of wild fish. The pond is left to stay with full for at least two weeks before stocking. During this period sufficient quantities of natural food organisms develop
In addition to the green plants, the pond water also becomes rich with small animals that are good food for fry.
These are the most suitable food items for fry. Farmers would have to be shown by a technical person how to tell that these organisms are present.
The pond is now ready for stocking. But just before stocking, the pond should be fished through with a net twice or three times. This is done to remove any wild fish, frogs or any other animal that may have entered the pond while it was filled with water so that it is free for stocking.