In north India, the summer months (March/April to October/November) are favorable for fish farming; where a few smart management tips can boost production and farmers' income significantly. It is important to protect the fish stock from temperature
exceeding 35°C, informed Dr. Meera D. Ansal, Dean of College of Fisheries, Guru Angad Dev Veterinary & Animal Sciences University. Hence, during peak summer months the farmers shall maintain 5-6 feet water depth to provide comfortable space to the fish below the hot surface layer.
She cautioned to monitor ‘Oxygen’ levels during this period, which may fall to lethal levels during dawn due to enhanced biological activity in the pond; and advised to aerate the ponds during early hours of the day before sunrise, either by adding fresh water or using aerators, to maintain optimal oxygen levels. If fish are seen gasping for air at water surface, provide aeration, add fresh water and suspend manuring and feeding till water quality improves. Periodic water exchange will further augment fish growth and production. For the said purpose, nutrient rich pond water can be used for irrigating the paddy or other agriculture fields, which will improve the pond water quality and reduce the crop fertilizer requirement as well.
Sustained natural food (plankton) production in the pond and feeding as per recommended regime helps in achieving optimized production targets. For sustained plankton production, manure the pond in a phased manner with split doses. Use farm made pellet feeds to reduce feed wastage and achieve better feed conversion efficiency. In case water turns dark green/brown/greenish brown in color or algal blooms appear on the water surface, suspend manuring and feeding till the condition improves back to normal. Also check day-night variation in water pH, which may cross 9.5 during peak day hours and fall below 7.0 during night hours. Maintain optimum pH range (7.5-8.5), with lime or alum/gypsum application as per expert advice.
Farmers shall refrain from overstocking and overfeeding or over 
manuring the ponds for achieving higher productivity. It enhances input cost and also deteriorates the water quality. Further, ammonia toxicity increases with increase in temperature and pH, leading to stress and subsequently disease outbreak or mortality. Under such conditions, keep the ponds well aerated, add common salt and apply gypsum/alum as per expert advice.
For disease management in fish farming the golden rule is “Prevention is Better than Cure”, as disinfection of large pond water volume is a costly affair and unlike terrestrial animals, individual treatment of underwater fish is not possible. Dr. Meera advised the farmers to follow the recommended prophylactic measures with application of lime (50-100 kg/acre, if pH< 8.0), potassium permanganate (1-2 kg/acre) or ‘CIFAX’ (400 ml/acre) to maintain fish health; take care of recommended biosecurity measures to check entry of harmful pathogen; and in case of any disease, consult an expert for proper diagnosis and treatment.
