Koi is a tasty fish that everyone enjoys, and no spread for guests is complete without it. That is why it is so highly valued, and why koi need care. Farmers need to know about its diseases and their remedies.

Apart from ulcer disease, no other disease is seen in koi. Usually the fish that are returned to the pond after sampling checks later develop ulcers, which can then spread widely. Frequent netting can also bring on the disease.

Ulcer disease in koi spreads very quickly, so action must be taken in time. Mix 1 kg of salt per decimal with water and spray it over the pond. Apply again at the same rate a week later.

Thai koi usually get ulcer disease in winter, so the fish should be sold before winter arrives. With good management, however, fish can be kept in stock through the winter too:

• Change the water at least once a week, lowering it by 2 feet and adding fresh water.
• Spray 1 kg of salt per decimal over the pond every 15 days.
• Bring stocking density down to between 150 and 200 fish per decimal.
• In winter, always use floating feed. Wasted feed can also cause disease.
• Check the health of the fish every 15 days.
• If any sign of disease appears on the fish, sell them at once. Diseased fish fetch no price.
• Never net extensively except when harvesting for sale.

Source: Jagonews24. First published in Bengali on The Agro News.