The Recirculating Aquaculture System (RAS) effectively integrates agriculture and aquaculture but faces challenges in selecting suitable plant species for treating wastewater in brackish environments. This study evaluates Sesuvium portulacastrum L. for its potential to improve water quality and nutrient cycling in a batch and aquaponic system (four-tank system), which includes tanks for whiteleg shrimp, tilapia fish, and wastewater recovery. Results showed that 1 g of S. portulacastrum processed 0.397 mg NH₄⁺, 0.030 mg NO₂⁻, 5.276 mg NO₃⁻, and 2.477 mg total phosphorus. Shrimp weight increased from 4.6 g to 16.5 g, while tilapia weight increased from 30 g to 67 g. Key water parameters remained stable in the S. portulacastrum model compared to the control. This improved RAS model demonstrates an energy-efficient and effective solution for water and nutrient cycling, applicable in both small-scale urban and large-scale aquaculture systems.