In order to study the effects of some plant extracts on Macrobrachium rosenbergii cultivated in fiber tanks, freshwater prawns were randomly divided into eight groups: a control group was fed with basal diet, and seven treatment groups in two replicates fed with basal diet supplemented with 0.05%,  of peanuts,  Arachis  Hypogaea (A), 0.05% of sesames, Sesamum  Indicum (B) and 0.05% of  sun flower seeds, Helianthus Annuus (C) also using mixture from them under the same proportion as (AB), (AC), (BC) and (ABC) extracts for 12 weeks, respectively. experiment were conducted on fresh water prawns Macrobrachium rosenbergii post larvae (PL) with an average initial body weight 0.09 ± 0.01^a g was obtained from Fish Hatchery, Mariut fish farm Company, Alexandria Governorate, Egypt. Water quality parameters, temperature, salinity, dissolved oxygen, pH, ammonia, nitrate and nitrite were monitored.  The experiment lasted 84 days and biomass gain was evaluated every two weeks. Final biomass, survival rate and feed conversion rates were calculated at the end of the experiment. Results revealed that,  The final weight obtained by the prawn fed diets contained (B), (AB) and (A) extracts is significantly at (P<0.05) higher than the fish fed the same diets with other extracts as (ABC), (AC), (C) and (BC); being 8.13 ± 0.24, 7.55 ± 0.21 and 7.31 ± 0.15 respectively in the formers and 6.76 ± 0.23, 5.43 ± 0.22, 4.75 ± 0.12 and 4.23 ± 0.07 respectively in the latter's against control as 3.62 ± 0.04. In general, the maximum value (8.13 ± 0.24) was recorded in the prawn fed with diet contained extract (B) and the minimum value (4.23 ± 0.07) occurred in the prawn fed with diet contained extract (BC). The highest protein intake was obtained by the diet with (B) and (A) extracts and the lowest in the diet of  (BC) extract; the proportions being 9.48 ± 0.04^a and 9.38 ± 0.18^a in the former and 7.22 ± 0.08 in the latter. The highest feed conversion ratio was obtained by the diet with (BC) and (C) extracts and the lowest in the diet of (B) extract; the proportions being 3.90 ± 0.10^ab and 3.66 ± 0.08^b in the former and 2.62 ± 0.06 in the latter.