Harvest the fish according to prevailing market price and demand.
Harvest some of the fish like Catla and Silver carp as they grow to marketable size within 3–4 months of stocking.
You can follow multiple harvesting and restocking schedule. Replenish the stock after harvesting by restocking with same species and number of fingerlings.
Do final harvesting at least once in a year depending upon market price and availability of fingerlings for immediate stocking of pond without loosing culture time.