Fish lice disease causes a range of problems for fish farmers, and many do not recognise it. Here is detailed information on how to prevent, identify and treat it.

Fish are infected by an external parasite called Argulus. The parasite sucks blood from the fish's body and causes wounds.

The lice cling to the body surface and fins. Infected fish rub their bodies against anything hard and jump about. The body bleeds, and the parasite can be seen with the naked eye. The fish swim restlessly, and the area around the affected spot turns reddish.

• Keep the pond clean.
• Apply lime at 1 kg per decimal.
• Reduce the use of organic fertiliser.
• Remove infected fish from the pond.
• Apply Dipterex (Dylox, Neguvon, Tuguvon) to the pond at 0.5 ppm, once a week for five weeks in a row; or apply Sumithion at 0.8 ppm, once a week for five weeks in a row; or bathe the fish in a 0.25 ppm potash solution for five to six minutes.

The information in this report was taken from the fisheries section of the Agriculture Information Service.

Source: Staff Correspondent. First published in Bengali on The Agro News.