Types of Fish Ponds for Successful Farming

Ponds can be categorized based on their water supply, drainage systems, building materials, and purpose. A single pond can serve multiple functions depending on the time and evolution of the installation.

The essential components of a fish pond consist of a pond skimmer, a biological filter/falls, aquatic plants, pond rock/gravel, and fish. These components work together to create a healthy and balanced environment for the fish. The pond skimmer helps maintain clean and clear water, while the biological filter/falls provide natural filtration.

Aquatic plants not only enhance the aesthetic appeal of the pond but also contribute to regulating water quality and providing oxygen for the fish. Pond rock/gravel adds to the overall visual appeal and provides a surface for beneficial bacteria to grow. Finally, fish are the main inhabitants of the pond, bringing life and activity to the ecosystem.

Now let's explore the different types of ponds:

(a) Barrage ponds: In barrage ponds, water from a source flows through a narrow river, which can be dammed to create a pond. A sluice gate is installed at the front of the dam to control drainage.

(b) Diversion ponds: Unlike barrage ponds, which retain all the water from a stream, diversion ponds only use a portion of the water. These ponds are generally less expensive, have a lower flood risk, and drain quickly.

When it comes to pond size and depth, several factors come into play:

Size: The size of a pond is determined by various factors, such as its intended use, the quantity of fish to be produced, the level of management required, and the availability of resources. Subsistence ponds are smaller, while small-scale commercial ponds are larger, and large-scale commercial ponds are the largest.

In terms of area, subsistence ponds should be between 100-400 square meters, small-scale commercial ponds between 400-1000 square meters, and large-scale commercial ponds between 1000-5000 square meters.

Depth: Fish ponds are typically shallow, with a maximum depth of 1.50 meters. The shallowest part should be at least 0.50 meters to control the growth of aquatic plants. Deeper ponds are more expensive to construct, but may be necessary for dry areas to store enough water for the dry season.

To construct a fish pond, specific steps should be followed:

1. Planning the pond layout and construction plan.
2. Clearing the site after marking the boundaries.
3. Installing a water supply channel against the water current to prevent debris from entering the pond.
4. Building drainage channel canals after completing the pond.
5. Marking the boundaries of the ponds through picketing or staking.
6. Constructing watertight dikes around the pond.
7. Arranging the base with a soft slope inclined towards the outlet.
8. Installing supply and drainage structures to manage water inflow and outflow.

Additional considerations include:

(a) Oxygenation of Water: Increasing the surface area of contact between air and water helps increase the supply of oxygen in the pond.

(b) Limiting Pond Erosion: Placing erosion-resistant stone blocks at the water inlet prevents erosion.

(c) Filtration: Water filtration devices at the inlet improve water quality by reducing turbidity and eliminating suspended organic matter. They also limit the introduction of wild fish and carnivorous species.

(d) Pond Drains: A well-constructed fish pond should have drains to maintain optimal water levels and enable complete draining during fish harvest.

(e) Sedimentation Tanks: These tanks remove mineral and soil particles from turbid water, improving water quality.

(f) Biological Plastic: Using "biological plastic" helps reduce water seepage by covering the base and dikes with an impermeable material, such as waste from a pigsty.

(g) Fencing: Fencing is an effective barrier to prevent predators from entering the pond enclosure. It should consist of buried netting, with sturdy stakes made of metal or non-rotting wood erected at regular intervals. The fence also helps reduce spawning, which can lead to pond abandonment. Access to the pond enclosure should be controlled using doors, and additional measures like coarse nets or scarecrows may be necessary in areas with high populations of fish-eating birds.

(h) Filling the Pond and Testing the Water: It is advisable to fill the pond gradually to a maximum depth of 0.40 meters at the outlet. The water supply should then be shut off, and the pond should be kept filled for a few days. During this period, the dikes should be thoroughly inspected, and any crevices or collapsed sections should be repaired, ensuring proper compaction of the earth.

After draining the water completely and leaving the pond dry for a few days, the dikes should be checked and repaired as necessary. The pond can then be filled slowly again, to a maximum level of about 0.40 meters higher than before.

The water supply should be shut off, and the dikes should be inspected and repaired after a few days. This filling and drying process should be repeated until the water level in the pond reaches its maximum level. Throughout this process, regular checks and repairs of the dikes are essential to ensure maximum security and efficiency.

Conclusion

In conclusion, the construction and management of fish ponds require careful consideration of various factors. Ponds can be classified based on their water supply and drainage systems. The size, shape, and depth of a pond play a crucial role in determining its purpose and the types of plants and animals it can sustain.

Constructing a fish pond involves specific steps and considerations, including the installation of essential components, managing water supply and drainage, and implementing measures to enhance pond quality and prevent erosion. By following these guidelines, farmers can create and maintain healthy fish ponds that contribute to successful aquaculture operations.