Freshwater prawns, Macrobrachium rosenbergii were reared in four ponds selected in the Gangetic delta (22°10'21.74"N; 88°53'55.18"E) at a density of 2 individuals m-2 for 180 days. The average initial weight of the seed was 0.08±0.01 gm and post larvae were given measured amount of feed (considering their age and biomass) as per the standard protocol usually followed in the present geographical locale. The prawns of the selected ponds were fed with four different types of feed. The conventional diet was provided by feeding the prawns with a commercial feed having animal origin ingredients (like trash fish dust, shrimp head dust etc.). Three experimental diets (PC10, PC20 and PC30) were prepared by mixing the dust of Porteresia coarctata (salt marsh grass) in different percentages (10%, 20% and 30% respectively) with the normal soybean based meal of plant origin Significant difference was observed in the production of the harvested prawns due to different diets. The highest production was recorded from culture pond where the prawns were fed with formulated feed having 30% salt marsh grass (Porteresia coarctata) dust (PC30). Duncan's multiple range test showed significantly higher (p<0.05) daily growth rate (0.33±0.20 gm day-1), specific growth rate (3.75±0.01), survival rate (79.0±1.00%) and lower FCR (1.12±0.02) in prawns fed with PC30. The overall health of the culture pond (pond water and pond bottom soil) in terms of nutrients, chlorophyll a and soil organic carbon speaks in favour of the efficacy of the herbal additives that were added to the feed in case of experimental ponds. The highest production (in terms of yield area-1) from pond also supports the above statement.