Feasibility study of hybrid recirculating aquaculture system (RAS)–biofloc application in aquaponic Nile tilapia ( <i>Oreochromis niloticus</i> ) nursery and tatsoi ( <i>Brassica rapa</i> var. narinosa) cultivation systems

Aquaponics offers a promising solution to meet growing food demand. We evaluated the feasibility of producing nursery-sized Nile tilapia and tatsoi using a hybrid recirculating aquaculture system (RAS)–biofloc approach to assess the biological, technical, and financial aspects. The study followed five key steps: system installation, cultivation, biological, and water quality assessments, technical analysis, and financial evaluation. Results showed favorable growth, with Nile tilapia reaching 63.92 g/individual (SGR: 1.32%/day; FCR: 1.83) and tatsoi yielding 70.26 g/plant over 28 days. Water quality parameters such as pH (6.9 to 7.8), temperature (23.2 °C to 26.4 °C), and dissolved oxygen (3.6 to 4.5 mg/L), was within optimal ranges. Technical reliability was demonstrated by stable system operation. Financially, the benefit–cost ratio ranged from 1.55 to 1.80, and the internal rate of return reached 33% to 37%, indicating profitability. Therefore, the hybrid RAS–biofloc system is biologically, technically, and financially feasible for industrial-scale cultivation.