Pests and predators are the major problems encountered by the traditional farmers. Even when the selective stocking method is followed after screening the water intake, the entry of larvae/eggs of some of the unwanted species cannot be avoided. Before intimation of a new culture, it is essential that all unwanted organisms are removed from the pond. In drainable ponds, this is achieved by drying the pond bottom.
In cases where complete drying is not possible, organic, biodegradable piscicides such as Mahua oil cake and tea seed cake can be used. No chemical piscicide should be used. After the application of the piscicide, at least a minimum period of 10 days should be given for its toxic effect to be degraded.

Piscicides like Mahua oil cake (100-150 ppm) and tea seed cake (15-20 ppm) act as organic fertilizers after their toxicity is eliminated. The piscicides are applied with a minimum of water. The water dosage is calculated on the basis of the volume of water as given in the following table