Stocking of healthy seed (post-larvae) solves most of the disease problems that are encountered by farmers. Only hatchery-reared and healthy seed should be used. The quality seed is characterized by active movement against the current in the container; absence of bright colouration; and adaptability to stress conditions of reduced salinity and formalin content. The presence of viral and bacterial pathogens/ diseases should be identified by trained microbiologists.

The number of seed stocked has a strong bearing on its growth rate during culture. The stocking densities should be decided on the basis of the management practices followed. For improved traditional systems, the stocking densities should be in the range of 4-6 no./m2.