Use of Feed:
The growth of fishes in any pond has direct relation to the available amount of food in that pond. The naturally available food is the most economical source of nutrients, but these foods are not in sufficient amount to support proper growth and development of the fishes. Therefore, feeds must be provided artificially to ensure maximum growth and yield. The food in the pond can be divided into two groups based on their nature of origin:
These foods include plankton, aquatic animals and plants. They are naturally produced in the pond and are the cheapest source of food for fishes. These foods can be maintained in the pond by proper management of the pond. They are; plankton (phytoplankton and zooplankton), aquatic animals (snails, insects. aquatic worms, small crustaceans, etc.), detritus (organic matters at the bottom of the pond covered by microorganisms), aquatic (Wolffia, Spirodela, Lemma, Hydrilla, Eichhornia, and Pistia) and terrestrial plants.
ii)Artificial food/ Formulated feed:
These food are derived from plant and animal sources but are n processed in some way. They are directly given in the pond as supplementary food in order to promote growth of fishes. These feed may vary depending upon the fish species. Based on the source, there are two types of formulated feed:
They are prepared from plants for fish culture. For example. oilcakes (mustard oil cake, soybean cake, cotton seed cake. peanut cake, sesame cake, and sunflower seed cake), grains (wheat, rice bran, wheat bran, barley, oats, sorghum, etc.)
They are the major source of protein (30-80%) in fish feeds They possess high nutritional value and they are made from a variety of sources, such as by-products from mest processing factories, slaughter houses and silk factories, meal, shrimp meal, bone powder, blood powder and feather powder. They have well-balanced amino acids and have high levels of vitamins which are necessary for growth of fishes. They are essentially used for feeding carnivorous
Management of Fish Pond
The major importance of providing feed to the fish is that, under natural conditions, fishes might not grow to their maximum marketable size under desired time period. Thus, it is essential to provide formulated feed to the fish, in order to ensure their maximum growth and development.
Use of Fertilizer
The fish ponds are fertilized in order to improve fish production. Fertilizers containing nitrogen, phosphorus and potassium (especially phosphorus) stimulate the growth of microscopic plants and animals which are known as phytoplanktons and zooplanktons respectively These phytoplanktons and zooplanktons serve fishes (aquatic animals) in food chain. In recreational ponds, an as food material for the abundance of plankton supports larger population of species of fishes In the fish ponds used for commercial production of juvenile fish, plankton the primary food source. The phytoplanktons also help in absorption of oric nitrogen wastes and raise daytime dissolved oxygen concentrations so they are important to water quality.
Pond fertilization is one of the management practices which helps to increase the productivity and maximum carrying capacity of the fish pond. Fertilization is done to develop natural food and save the formulated feeds. Generally, use of fertilizer provides nutrients to encourage rapid growth of phytoplanktons. These phytoplanktons are primary producers in the fish pond. The other entire organisms depend upon the primary producers, and once the phytoplanktons increase in number, the series of food chain is activated. This results in increased fish production ultimately.
Based on the nature of origin, the fertilizers that are used in the pond can be divided into two groups, viz organic fertilizers and inorganic fertilizers.
When to fertilize the pond?
When not to fertilize the pond?
Application of fertilizers:
Organic fertilizers can be applied by making heaps at the corner of a pond. Chemical fertilizers can be applied by broadcasting.
There should be adequate sunlight, optimum dissolved oxygen, conductive temperature, no wind and proper water level in the pond while applying fertilizers. It is ideal to apply fertilizers in the early hours of the day, about 2-3 hours after sunrise. (Dr. M.K. Shrestha, et al., 2017).