The implementation of on-grid PV systems was conducted to ensure a continuous supply of electricity. This article discusses implementing an on-grid PV system in a fish farm that requires a continuous electricity supply. Continuous electricity is used to power the aeration system. The aeration system is critical in determining whether or not fish farmers can harvest well. An electric motor drives the water wheel in the aeration system, circulating oxygen in the fishpond. Based on the design, operation, and economic parameters, a comparison is made between the proposed system, namely the PV system, and the current system, namely the grid with a diesel generator as a backup. The nominal discount rate, diesel fuel price, and grid reliability level have all been subjected to sensitivity analysis. The Hybrid Optimization of Multiple Energy Resources software was used for the study. The results show that the on-grid PV system can continuously provide electricity to meet the demand for fish farming. The proposed system has a net present cost that is 20% lower than the net present cost of the current system. The cost of energy generated by the on-grid PV system is also 27% less than the cost of energy generated by the current system. Changes in fuel prices do not result in changes in net present cost for all levels of grid reliability to produce continuity in electricity supply. The nominal discount rate strongly influences the net present cost, the higher the nominal discount rate, the lower the resulting net present cost.