Moreover, NH4+-N and NO2−-N concentration are important indicators for growth of shrimp. If these concentration were higher than expected value, there would be a deterioration ofenvironment. The results of the present study removed significant concentrations of NH4+-N and NO2−-N from aquacultural pondsmainly due to the presence of ammonifying bacteria and nitrifying bacteria.The direct contribution of water spinach to the P removalattributed to the high P-uptake capacity of water spinach (Li et al.,2009). We could see from Fig. 4 that phosphorus content in everyorgan of water spinach was almost increased as time elapsed, andthe average phosphorus assimilation rate was highest in stem,which is different from the change of nitrogen content in organs of water spinach. The results showed that water spinach could assimilate large amounts of phosphorus from water body, which might be the main mechanism for phosphorus removal by water spinach in aquatic water In summary, we found that the removal mechanism of ammonia nitrogen and nitrate nitrogen by water spinach were primarily by microorganism, whereas the removal mechanism of phosphorus by water spinach was mainly by plant absorption. Water spinach is as an edible and floating plant with very high marketable valuecompared to many other aquatic macrophytes, makes it perfect choice for N and P removal (Karnchanawong and Sanjitt, 1995).