While constructing a new pond, the soil quality of the site should be tested at first. Sandy soil should always be avoided. Soil with clay loam texture is favourable for new fish pond construction. If possible, a soil sample for the site of new pond construction should be tested in a Soil Testing Laboratory to ensure its suitability. Sites nearby to natural waterbodies like rivers should be avoided. Water table data of the site should be collected.
Generally rectangular ponds (Length: Breadth 3:1) are better from management point of view. Size of a pond depends on the type of culture. Recommended sizes are:
Nursery pond: 0.01-0.05 ha
Brooders' pond: >0.15 ha
Rearing pond: 0.1-1.0ha
Ideal depth of ponds:
Nursery pond: 1.0-1.5 m
Rearing pond: 1.5-2.0 m
Stocking pond: 2.5-3.0 m
Fishes should be fed with supplementary feed @1-5% of the fish biomass of the pond.
Feed to be applied = No. of fish x Average weight x Feeding rate (% biomass/100)
Liming is very necessary for fish culture operations in the state of Assam as the natural pH of soil of this region is acidic in nature. Farmers should regularly apply lime as per the suggestions of Subject Matter Specialists/ Fishery Officer based on the pH of their culture pond.
Generally for semi-intensive fish farming the stocking density should be maintained as follows:
Carried over seed/ Fingerling: 8,000-10,000/ ha
It is very difficult to identify good quality fish seed by visual observation. However, disease free fish seed collected from Govt approved hatcheries showing active movement, shiny colouration and minimum mortality are considered as good quality fish seed.
We can get good quality fish seed from Govt. approved hatcheries.
Fishes may gulp in water surface due to many reasons like more than recommended stocking of fish seed in the pond, in case of any disease, pollution etc. If farmers observe gulping of fish in their fish pond they should immediately take remedial measures in consultation with experts.
Poor growth of fishes in culture ponds may be due to multiple factors like unfavourable pond environment, poor quality fish seed, improper feeding, disease incidence etc.
Farmers should regularly collect weather updates during monsoon season. In the event of flood, they should take some preventive measures to avoid escape of fish from ponds like: nylon netting in the pond embankment, construction of the embankment above the HFL of the area (if possible), repairing of weak embankments of the pond before commencement of monsoon.
Reddish or brownish layers on pond surface may be caused by algal blooms. Such types of blooms like Microcystis may be toxic to fishes sometimes leading to death of fishes. If such layers are observed in fish ponds, farmers should immediately stop feeding & fertilization in such ponds until the bloom disappears. Farmers can physically remove the bloom layers with the help of fishing nets. In case of persistent blooms, they should consult experts.
