This article throws light upon the top eight physico-chemical features of pond water for fish culture. The features are 1. Light 2. Temperature 3. Turbidity 4. Dissolved Oxygen Content 5. PH Level 6. Carbon dioxide 7. Nitrogen and Phosphorus 8. Aquatic Fauna and Flora.
Physico-Chemical: Feature # 1.
Light is a complex environmental factor and its penetration into pond water can produce diverse ecological effects. The phytoplankton, zooplankton, organic and inorganic particles and turbidity of water, reflects or absorb the light rays, which supplies energy for the process of photosynthesis in plants. Light also provides oxygen and food to the fish and the organisms of water, serving as food for fishes.
Physico-Chemical: Feature # 2.
The range of temperature prevailing in pond water imposes definite limitations upon the choice of fish to be cultivated, because different fishes have different ranges of temperature-tolerance. Water temperature in range of 20-37°C is favours al major carps growth.
Physico-Chemical: Feature # 3.
Turbidity is mainly due to plankton growth or due to suspension of silt and clay particles. Indian major carps can tolerate turbidity up to 2000 ppm. Turbidity affects penetration of sunlight and therefore is unfavorable to photosynthetic activity in the pond water affecting primary productivity.
Physico-Chemical: Feature # 4.
Dissolved Oxygen Content:
Aquatic living organisms need dissolved oxygen in water for respiration and in exchange release carbon dioxide. Carps need 6-7 mg/litre dissolved oxygen for aquatic breathing.
Physico-Chemical: Feature # 5.
Generally, neutral or slightly alkaline (pH-7.8) water is more productive than acidic water.
Physico-Chemical: Feature # 6.
Carbon dioxide comes into the pond-water through decomposition organic materials, respiration of various organisms and from the atmosphere. It is useful for the green plants.
Physico-Chemical: Feature # 7.
Nitrogen and Phosphorus:
0.2 ppm of dissolved nitrogen is considered favourable for better productivity. The optimum limit of nitrogen can be in the range of 0.3 to 0.3 ppm. 60-120 ppm of phosphorus is supposed to be ideal for high productivity.
Physico-Chemical: Feature # 8.
Aquatic Fauna and Flora:
Pond should be rich in aquatic fauna and flora. It definitely increase the productivity or the pond phytoplankton and zooplankton that are consumed by the fishes.