Fish is one of the sources of protein. Fish is one of the largest commodities from aquaculture. Fish farming is one of the economic supports for the community, especially around the waters in Indonesia. Aquaculture in Indonesia uses river water and tidal seawater as the main water source. Changes in water quality due to pollutants in the water can affect the quality of pond water. Horizontal Subsurface Flow Constructed Wetland (HSSF-CW) technology can increase the efficiency of organic matter removal. The aim of this study were to identify the water quality of fish pond and performance of HSSF-CW technology in improving fish pond water quality. The media in reactors were gravel and sand with plants (Bruguiera gymnorrhiza and Avicennia alba). Dimension of reactor were 65x60x40 cm3 and it were made from polymethyl methacrylate. There were 10 reactors, namely K1 (without plants and without flow rate), K2 (without flow rate), A1Bg (raw water+4 mL.min-1+B. gymnorrhiza), A2Bg (raw water+8 mL.min-1+B. gymnorrhiza), A1Aa (raw water+4 mL.min-1+A. alba), A2Aa (raw water+8 mL.min-1+A. alba), B1Bg (effluent+4 mL.min-1+B. gymnorrhiza), B2Bg (effluent+8 mL.min-1+B. gymnorrhiza), B1Aa (effluent+4 mL.min-1+A. alba), and B2Aa (effluent+8 mL.min-1+B. gymnorrhiza). The reactor were operated continuously with flow rate (4 mL.min-1 and 8 mL.min-1). Analysis of Total Suspended Solid (TSS) used gravimetry method and salinity used argentometri titration. The spectrophotometers analysis were conducted to determine of COD, PO43-, NH4+, and NO3-. In conclusion, the largest removal efficiency of raw fish pond water on COD, TSS, PO43-, NH4+, and NO3- parameters were obtained in reactor A1Aa (83.86%), A1Bg (89.53%), A2Bg (24.06%), A1Aa (84.83%), and A2Aa (93.77%). The greatest removal efficiency of effluent pond on COD, TSS, PO43-, NH4+, and NO3- parameters were obtained in reactor B1Bg (85.46%), B1Bg (91.21%), B2Bg (92.29%), B2Aa (86.81%), and B2Bg (96.84%).