The production capability of a pond can be determined by observing the physical qualities of water. The physical qualities of water and its impact in fish farming in the cultivated pond are described below.
Slightly green colored water indicates the high production of a pond. The color of the water may different due to presence of various types of organic and non organic substance. The production energy can be guessed by watching the color of water. The water become yellow colored if there are lack of nitrogen in the water. The water become black colored due to lack of phosphorus. Carbon dioxide become less in gray colored water. The water become deep green colored for excessive moss and it is very harmful for fish. If the excessive moss are not use as food then it creates very harmful gas in the basal area of the pond.
Depth of water is very important for fish farming. The depth of water would be at least 1.5 miter to highest 3 miter. But 2 miters depth is an ideal depth for successful fish farming. Depth of water particularly controls the physical and chemical qualities of water. Rate of oxygen, presence of natural food of fish etc. depends on the depth of water. The sunlight can’t reach the basal level of pond if the depth of water become very high and it hinders the sufficient production of natural food. As a result the fish suffers by lack of oxygen and the growth of fish get obstructed. On the other hand if the depth become less then water become hot quickly and harmful aquatic weeds may grow.
Muddy and Transparent Water
The production ability of pond become high if the transparency of water become 25cm. Muddy water influence the food demand of fish. The sunlight can’t enter in the water due to muddy water. As a result plankton production get reduced and hampers the growth of fish.
Fish are cold blooded animal. The body temperature of fish increases and decreases with the temperature of water. So, the growth rate of fish is directly related to the temperature. Tendency of consuming food get increased if the temperature get increased. And fishes eat less food in low temperature. For this reason decrease the supply of supplementary fish feed in the pond in winter season. 25°c-30°c temperature is perfect for farming rui and some other carp fish.
Primary productivity like production of phytoplankton depends on sunlight. Entrance of light in the water of pond can be obstructed in various ways. For example, giant trees in the shore, muddy water, aquatic weeds etc. obstructs the entrance of sunlight into the water. Cut the branches if there are any big trees in the shore of pond. Muddy water obstructs the entrance of sunlight fatally. As a result it stops the production of plankton. Different types of aquatic weeds are also obstruct sunlight. Remove those weeds from the water. Plankton production get reduced if the entrance of sunlight in the water get congealed. As a result fish production also get reduced.