The state seeks to develop fish farming projects and raise their productive and economic efficien-cy, Damietta governorate is characterized by the diversity fish production sources, as it ranked second after Kafr El-Sheikh governorate at level of the Republic, however, the relative importance fish pro-duction decreased from about 14.90% in 2018 to about 7.38% in 2020. and the relative importance of fish farming decreased from 16.95% to about 7.78% during that period. The research aimed to meas-ure efficiency of the investment performance of fish production projects according to the quality of irrigation water for fish farms (fresh, lake, sea), using: Benefit/Cost Ratio ،Payback Period of the Capital ،Internal Rate of Return (IRR) ،Sensitivity Analysis،, and Two way Anova Analysis. The most important results:(1) The investment costs of fish production farms with fresh water and sea water are close compared to lake water.(2) Net return has about 588, 220, 377 thousand pounds/farm/year for each of them, respectively.(3) The internal rate of return for investment for fish production projects was about 45.42%, 31.48%, and 43.83%, respectively.(4) The project has the abil-ity to achieve profits when increasing the investment cash outflows by 20% and reducing the invest-ment cash inflows by about 30% in fresh water, with an expected net flow about 465 thousand pounds, and expected (IRR) 1.75%. and fish production project in lake water, when the incoming and outgoing cash investment flows increase by 20%, an expected net inflow about 132 thousand pounds, and ex-pected (IRR) 2.02%, as well as fish production projects in seawater expected net cash flow 1.72 mil-lion pounds, and an expected (IRR) 11.42%.The research recommends Encouraging investors in the field of fish farming on sea water due to the high internal rate of return and given the limited fresh wa-ter resource.