Fish farmers across the country face a range of challenges during the winter season, as falling temperatures significantly disrupt fish feeding behavior, metabolism, and overall pond ecology. In cold conditions, fish reduce their intake of feed, which often leads to uneaten feed decomposing in pond water. This process increases ammonia levels, while reduced water circulation and diffusion limit the availability of dissolved oxygen. Together, these factors can result in stress and, in severe cases, mass fish mortality.
In confined ponds, cold water causes fish to reduce movement, slowing their metabolism and further suppressing appetite. At the same time, lower water temperatures increase the prevalence of various diseases. Shorter daylight hours mean reduced exposure to sunlight, preventing adequate warming of pond water and further lowering water temperature.
Fish digestion and metabolic activity are optimal at temperatures between 28 and 32 degrees Celsius. When temperatures fall below this range, digestion slows and growth rates decline accordingly. Reduced sunlight also limits natural oxygen production in ponds, making respiration difficult for fish. In oxygen-deficient conditions, fish often surface and gasp for air, a clear sign of distress that can precede mortality.
The reduced formation of phytoplankton in pond water further compounds the problem. As phytoplankton levels decline, dissolved carbon dioxide concentrations increase, making respiration more difficult for fish. In addition, the reduction of natural food sources such as phytoplankton and zooplankton leads to feed scarcity, resulting in poor growth performance.
Water quality parameters also become unstable during winter. For healthy fish growth, pond water pH should remain between 6 and 8. When pH falls below 6, the water becomes acidic, causing fish to lose appetite. Conversely, when pH exceeds 8, the water becomes alkaline, and excessive alkalinity can lead to fish mortality.
Winter conditions also increase the incidence of parasitic, fungal, and bacterial diseases in fish. Without proper care, fish may suffer from lice infestations, malnutrition-related disorders such as blindness and skeletal deformities, ulcer disease, tail and fin rot, gill rot, and abdominal swelling, all of which can lead to significant losses.
To mitigate these risks, fish farmers are advised to adopt comprehensive winter management practices. Vegetation and tall trees along pond embankments should be cleared as much as possible to ensure adequate sunlight reaches the pond from sunrise to sunset. Artificial methods should be used to increase oxygen levels in pond water.
Oxygenation can be improved by netting, swimming through the water, or striking the surface with bamboo poles. In larger ponds or enclosures, artificial oxygen tablets such as SI Oxytab may be applied in the evening at a rate of four to five kilograms per acre.
Dragging nets through ponds every 10 to 15 days helps farmers assess fish health, population density, and weight. This practice also releases harmful gases trapped at the pond bottom, improving overall water quality.
If fish mortality occurs due to ammonia toxicity, farmers may apply SI Amofree-L or SI Amofree-P at a rate of five milliliters per decimal, mixed with 20 milliliters of Chitagur. Excess algae, debris, water hyacinth, weeds, and other harmful aquatic plants should be removed regularly.
To maintain pond water pH within the optimal range of 6 to 8, farmers are advised to apply SI Biozeo Plus at a rate of six to seven kilograms per acre every 15 to 20 days or once a month at the onset of winter. If pH rises excessively, two liters per acre of vinegar or an acidifier such as Acidine may be applied. In cases of low pH, SI Royal Geo should be applied at a rate of 15 to 20 kilograms per acre.
To promote phytoplankton growth, inorganic fertilizers, particularly urea at four to five kilograms per bigha per month and triple super phosphate at five to six kilograms per bigha per month, should be soaked for three days before application. Additionally, SI Phytogro may be applied at three to four liters per acre during periods of strong sunlight.
To support balanced growth during winter and improve digestive efficiency, farmers are advised to mix high-quality enzyme-based growth promoters such as SI Growfish with fish feed. This helps stimulate appetite and improve feed utilization. Alongside this, a premium immunomodulator jelly such as SI Royal Gel should be mixed at a rate of 10 milliliters per kilogram of feed and administered continuously for 15 to 20 days.
As pond water levels typically decline during winter, adequate water supply should be ensured, and fish stocking density should be kept at normal or reduced levels. If pond water becomes excessively polluted, partial water exchange is recommended. To prevent further contamination, granular soil probiotics such as SI Proclean may be applied directly to the water at a rate of six to eight grams.
When necessary, disinfectants such as SI Chlor-T may be applied at a rate of one tablet per decimal, along with copper sulfate pentahydrate 10 percent formulation such as SI Phytoclean at 30 milliliters per decimal.
Throughout the winter season, maintaining water quality is essential. Farmers are advised to apply a high-quality water probiotic such as SI Royal Pro at a rate of 500 grams per acre, mixed with two kilograms of red sugar in clean water, every 15 days to sustain a stable and healthy pond environment.
