Co-culture of newly domesticated shrimp, F. merguiensis, and green seaweed, C. lentillifera, was conducted in six cement tanks to assess their impact on water quality and immunological response. Shrimp juveniles (14,3±0.3 mg) were stocked at a density of 50 shrimps/m2 and co-cultured with C. lentillifera at two initial stocking rates: A (0.1 kg/m2), B (0.2 kg/m2), and C (without seaweed) as a control treatment. All treatments were replicated twice, and the trial lasted eight weeks. The results of the experiment demonstrated that co-culturing F. merguiensis with C. lentillifera not only improves water quality, primarily nitrogen (TAN, NO2, NO3) and phospate (PO4-) compounds, but also on immunological parameters (THC, DHC, PA, and PO activity) assessed. Shrimp production indicators improve significantly (p<0.05) after seaweed treatments. Furthermore, C. lentillifera grows at a pace of more than 10% per day and is suggested for co-culture with shrimp at a density of 0.1 - 0.2 kg/m2.