Prevention of early mortality: On the first day of opening the vat, (hatchery pond) i.e after 30 – 45hrs of fertilization and incubation, the vat water should be released to flush out slowly and gently fill it back to high level of the pond. This reduces the side effect of the unhatched eggs, pollution of water which can kill the fries in great numbers. The
vat water can be changed once a day for a week. The water to be used, should be stored in a tank for a minimum of 24hrs, so that pH level would normalize.
