In fish farming business, it is not right to stock your fish pond without a proper preparation and treatment of the pond and water. The pre stocking management is very important that it affects the success of any fish farming business. However, the type of fish pond preparation depends on the types of fish in use. Example; the fish pond curing is specially applicable to only concrete ponds. You can check How to construct different types of Pond.
Fish pond proper management is important because it contributes to the well-being and growth potentials of your fish and other aqua planktons. Therefore, learning how to effectively manage and treat your pond before stocking your fish is one of the Secrets of a successful fish farming.
Again, The principles of fish pond management procedures are basically the same for old and new ponds. Though there are minor contingent differences in pond preparation which generally involves lime and fertilizer treatment of the pond bottom and water management processes.
Fish pond liming and fertilization
The liming of the fish pond is very important as it helps to balance the pH of the water, reduce water from seeping out of the pond and helps in the fertility of the pond to phytoplanktons.
The acidity or alkalinity of your pond depends on the interaction between the mineral content of the water and the soil beneath the floor. In our post on Pond construction steps , it was mentioned that the ideal soil for fish pond construction is the clay soil. However, It will interest you to know that clay soils are usually acidic. The reason for clay soil’s acidity is their ability to hold free hydrogen ions regarded as high cation exchange capacity (CEC).1
Therefore, liming is a very critical factor in farm business especially the earthen pond or ponds with run offs.
What is pond liming?
Pond liming is a procedure of neutralizing the acidic content of a pond by adding bicarbonates or carbonates of Calcium and magnesium compounds. Most times, the challenging factor of pond liming is knowing when the pond liming will be beneficial or not. Before liming a pond, it is better to collect random water samples from the pond and test the pH with an indicator. If the total alkalinity of the water sample is less than 20 mg/L, then you will have to lime your pond.
Benefits of pond liming
The primary aim of pond liming is to manage the pH of your pond. However, there are other relationships between pond liming and other pond characteristics;
- Liming acts to improve the fertilization of a fish pond.
- It helps prevent wide swings in pH that usually affects the survival of your fishes.
- The liming process introduces calcium and magnesium to the pond which serves as nutrients for growth and development of the fishes.
- The mineral composition of the water prevents seeping of the pond water.
- Liming helps to regulate the hardness of pond water, the ideal hardness range is 75 to 250mg/L. At this concentration, the calcium contents of the water helps the fishes with bone and scale formation which is essential for osmoregulation and biological functions.
- Hydrated limes can be used to sterilize the pond against disease causing organisms as a pre stocking management procedure of the pond.
How to lime a pond
There are plenty of liming materials in the market including agricultural limestone, basic slag, slaked lime, quick lime and liquid lime. When considering the best liming material for your pond liming, the effectiveness and the cost of the material is necessary.
Quick lime (CaO) or slaked lime (Ca(OH)2) is not always a good choice for use because of two reasons. First, it is expensive. Secondly, they can make the pH of the water fluctuate and therefore, can stress the aquatic life. But, with experience many farmers have been using slaked and quick lime successfully.
The Basic slag and the liquid lime have satisfactory results when used to treat the pond but they have some characteristics that disqualifies them as the substance of choice for liming.
Consequently, the best material for liming for a beginner is the agricultural limestone. The agricultural limestone can either be CaCO3 (calcitic) or CaMg(CO3)2 (dolomitic) limestone.
The advantages of using agricultural limestone includes;
- It is cheap and readily available
- The liming process does not require any special skill. In other words, it can be applied without any special training.
- Agricultural limestone can significantly improve the alkalinity and hardness of the pond water.
- Limestone acts as buffers, they salt out of solution if the alkalinity of the water rises above normal.
- They are effective in controlling the seeping of the pond by interacting with the mineral substances at the bottom of the pond.
How to apply the Agricultural limestone
If the limestone is too coarse. It is important to reduce the particle size to finely crushed materials because of the following reasons; To improve its surface area, to improve its neutralizing capability and to prevent it from causing physical harm to the fishes.
Next is to broadcast 50 – 200 gm/ square meters over the entire dried pond bottom and left to dry on the soil for 14 days. The pond is then flooded up to 60 cm (above the knees).
Though liming improves the fertilization of a pond. There is still need to fertilize the pond as a way of pre stocking management or preparation of a pond. It can be said that the most common reason to lime ponds is to improve the response to fertilization.
However, further ferritization of the pond introduces Nitrogen, Potassium and Phosphorus (NPK) to the pond. These elements are beneficial to the growth of phytoplanktons and also a source of nutrients to the fish and other zooplanktons. Hence, Fertilization as a method of pond preparation is necessary as it helps provide natural food for the fishes.
Also, the presence of the blooming aquatic plants helps to deplete the concentration of nitrogenous waste and other wastes through respiration.
How to fertilize the pond
You can use any of the 2 types of manure to fertilize your pond before stocking your fish. Remember that fertilization precedes liming.
Application of inorganic manure (NPK, SSP, TSP etc) or preferably animal manures (e.g. Cow, pig, poultry etc) to already flooded ponds to stimulate natural fish food production.
- For inorganic manure; fill a jute bag with fertilizer and submerge it under water, OR dissolve the fertilizer inside a plastic bucket and sprinkle over the entire surfaces.
- Organic manure: Fill jute with the manure and tie to stake at various points in the water OR collect manure in a large tank then mix with reasonable quantity of water. After mixing use the liquid part of the mixture in the fish pond. For cattle dung (100 g/m2), Chicken (50 g/m2) Urea (2 g/m2), (TSP 5 g/m2) once in 2 weeks.
Fish Pond Curing
In addition to liming and fertilization, concrete fish pond require a special treatment and preparation known as curing. Curing is the process of controlling the rate and extent of moisture loss from concrete during cement hydration.2
Normally, newly constructed cement ponds leach out excess lime. This lime raises the pH of the pond and causes death and diseases to fishes. Hence, before stocking a newly constructed concrete pond, it is important that you neutralize these excess lime that will potentially leach into the pond water.
There are many ways you can cure your concrete pond. Here are the most common and cheapest methods of curing a fish pond.
The first method is to fill the pond with water to the brim so as to leach the lime in the the entire pond. Then, cover the pond with a hessian or gunny bags. Allow this set up to stay for a week. After that, flush the pond and refill it with water. Test the pH of the pond to confirm if it is safe for fishery. Repeat this process till you get the optimum pH for stocking your fishes.
The second method is to mix one-gallon household vinegar to each 200 gallons of water in your pond. Allow this setup to stay for three days, then flush and refill the pond with water.
In Conclusion, There are pre stocking procedures for the preparation and the treatment of your pond before stocking. These procedures does not only help your fish to thrive but also improve the market value of your fishes. These procedures includes; Pond Liming, Pond Fertilization and Concrete Pond Curing.