Abstract: This study developed a high-stability indicator film containing a roselle (Hibiscus sabdariffa) anthocyanin extract (RAE)-oxalic acid (OA) co-pigment indicator (RAO), investigated the stability of the RAO indicator and its effects on the structure and performance of the indicator film, and applied the film to monitor the freshness of channel catfish (Ictalurus punctatus). The results showed that the stability of the RAO indicator improved compared with single RAE indicator. Moreover, the film with the RAO indicator showed enhanced performance. The tensile strength and elongation at break of the indicator film increased from 16.10 MPa and 280.95% to 17.81 MPa and 349.45%, respectively. Its moisture content and water solubility decreased from 19.10% and 42.71% to 13.98% and 34.69%, respectively. Under conditions of 4 ℃, 45% humidity, and no light exposure, the RAO indicator film could be stored for up to 82 days (ΔE<5). When used for monitoring the freshness of channel catfish at 4 ℃, the indicator film changed from rose-red to yellow-gray as the fish spoiled, demonstrating its accuracy in monitoring the spoilage process and its great potential for freshness monitoring applications.