The persistence of antibiotics oxytetracycline (OTC) in aquaculture wastewater poses critical environmental and public health risks, including the proliferation of antibiotic resistance. To address these challenges, this research introduces a novel, eco-friendly photocatalytic membrane system by integrating composites of graphitic carbon nitride (GCN), a non-metal photocatalyst, with TiO synthesized via a green method (using neem leaves), onto a PES membrane. This innovative approach overcomes limitations in traditional liquid-phase photocatalysis, like catalyst recovery and inefficiencies in real-world applications. To enhance photocatalytic activity, GCN/neem-TiO composites with varying ratios were synthesized to tune optical and electronic properties of the photocatalysts. The 1:4 GCN/neem-TiO composite appeared as the optimal photocatalyst composite ratio, with a low work function (3.35 eV) and enhanced visible-light absorption. When incorporated onto the PES membrane, this composite facilitated effective OTC degradation, achieving 90.49 % degradation in OTC aqueous solution, and 72.35 % removal in real aquaculture water under fluorescence light irradiation. The 1:4 GCN/neem-TiO/PES membrane also able to maintain its performance across four recycling cycles. The photocatalytic membrane also demonstrated robust fouling resistance, with a total fouling ratio (R) of 17.85 % and a flux recovery ratio (FRR) of 98.00 %, significantly surpassing pure GCN-coated membranes. These results establish the GCN/neem-TiO-coated PES membrane as a sustainable and efficient solution for antibiotic remediation in complex aquatic environments. By leveraging environmentally friendly materials and addressing the operational limitations of conventional systems, this work provides a significant advancement in photocatalytic water treatment technologies, and offering scalable potential for addressing antibiotic pollution issue in diverse wastewater scenarios.