Water treatment, reuse, and reducing the nutrients loading to the aquatic environments are key ways to achieve sustainable aquaculture. The usage of aquatic plants is an effective and environment-friendly method for water treatment. This study was conducted to investigate the nutrient removal efficiency of aquatic plant Lemna minor by static test and flow test using a water recirculation system for rearing of African cichlid (Labidochromis lividus) fingerlings during 7 and 30 days, respectively. The growth performance of fish and water quality parameters were compared between the L. minor and control groups in triplicate. The results of static test showed that L. minor removed the total nitrogen ammonia (TAN) and total phosphorus (TP) by 43.7% and 52.38% after 48 h and 7 days, respectively. The results of flow test revealed that the survival rate (%) and growth performance including final weight, final length, weight gain, specific growth rate (SGR%), body weight increase (BWI%) and daily growth index (DGI) of fish cultured in a water recirculation system containing L. minor as a biofilter were significantly higher than the control (P<0.05). The utilization of L. minor decreased the concentrations of TAN, TP, electrical conductivity (EC) and total suspended solids (TSS) by 41%, 37.80%, 2.60% and 81.11% compared to the control after 30 days of cultivation period. The nitrate (NO− 3 ) concentration increased to the maximum level on day 20 and then it decreased significantly on day 30 in the L. minor treatment (P<0.05). These findings indicated that the usage of aquatic plant, L. minor could be considered as an effective biological method for water treatment in aquaculture.

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