• Repair the dykes and if possible level the pond bottom
• Trim the branches of marginal trees overcasting the pond
• Remove all the sub-merged, floating, rooted emergent and marginal weeds from the pond.
This is the best method. Dewater the pond, catch all the fish and allow the pond bottom to dry till the bottom soil cracks. Summer is the best time for this.
Poison the pond in case dewatering AND DRYING is not possible. Any of the following fish toxicant may be used.
Aluminium phosphide (Phostoxin/Quickphos/Selphos etc.)
Available in tablet form
Uniformly apply the desired quantity of tablets in the pond.
Net the pond after 1 to 2 hours to facilitate proper mixing of the toxicant and catch the affected fishes
Toxicity lasts for 5 to 7 days
However, sometimes inspite of the treatment some of the weed fishes like chanda, mola, tilapia, etc. may reappear in the pond. Works relatively better in shallow ponds.
|Av. Water Depth||Number of tablets|
|1||30 cm (1 feet)||1|
|10||30 cm (1 feet)||10|
|33||1.5 m (5 feet)||165|
|50||1.5 m (5 feet)||250|
Take fresh stock of bleaching powder, mix with water and apply uniformly to the pond
Net the pond after 30 minutes to facilitate proper mixing and catch the affected fish
Toxicity lasts for about 6–7 days.
It kills all the fishes, frogs, mollusc, parasites and other disease causing organisms. When you apply bleaching powder you need not apply lime.
|1||30 cm (1 feet)||900 g|
|10||30 cm (1 feet)||9 kg|
|33||1.5 m (5 feet)||150 kg|
|50||1.5 m (5 feet)||225 kg|
Apply the powder after mixing with water uniformly throughout the pond
Net the pond and catch the affected fishes
Shrimps are not affected
Toxicity lasts for about 7 days
|Av. Water Depth|
|Required quantity of rotenone|
|1||30 cm (1 feet)||35 g|
|10||30 cm (1 feet)||350 g|
|33||1.5 m (5 feet)||5 kg 800 g|
|50||1.5 m (5 feet)||8 kg 725 g|
Mohua oil cake
Apply the cake uniformly in the pond
Net the pond after 1–2 hrs. to mix the cake in the water and catch the affected fishes
After a week it promotes dense population of fish food organisms and hence initial manuring is not required
Toxicity lasts for 10–12 days
|Av. Water Depth||Required Quantity|
|1||30 cm (1 feet)||3 kg|
|10||30 cm (1 feet)||30 kg|
|33||1.5 m (5 feet)||500 kg|
|50||1.5 m (5 feet)||750 kg|
Repeated netting is suitable for only those ponds having no other fishes except carps. You can not catch predatory and weed fishes simply by netting. A few remaining of those fishes will breed and have sizable population in the pond.
COMMON PREDATORY FISHES FOUND IN POND
Apply unslacked lime at the rate of 1 kg/decimal following the poisoning or dewatering the pond. Put lime in earthen dugout pits on the dykes or in suitable container, mix with sufficient amount of water, allow to cool and apply uniformily throughout the pond. Alternatively the bag containing the lime can be put in the water and after some time the same may be dragged across the pond to uniformly distribute the lime.
Apply both Organic and Inorganic manure in the pond at least 6 to 7 days after liming.
Apply any of the organic manure at the following rate
|Name of Manure||Water Area||Quantity|
|Cowdung||1 Decimal||5–7 kg|
|Poultry/Duck droppings||1 Decimal||3–5 kg|
Apply 100 to 150 g of Urea, 50 to 75 g of TSP and 20 to 30 g of MP to each decimal of water area.