The edible active coating is a popular trend for fish preservation. A hybrid coating composed of chia seed gum (CSG) and Oleum ocimi gratissimi (OG) was investigated, aiming to evaluate its ability to extend the shelf life of chill-stored fish. Physiochemical changes such as sensory analysis, color, moisture state, trichloroacetic acid-soluble peptides, total volatile basic nitrogen content, lipid oxidation indicators including peroxide value and thiobarbituric acid reactive substances, as well as microbial indicators including microbial enumeration and microbiota composition about fillets were assessed to evaluate the antimicrobial and antioxidant capacities of OG/CSG coating. The results showed a reduction of 1–2 log CFU/g of microbial enumeration was achieved during storage. The Illumina-MiSeq high throughput sequencing results showed spoilage bacteria Pseudomonas and Shewanella were effectively inhibited (p < 0.05). OG/CSG coating retarded protein degradation, lipid oxidation, water loss, and discoloration at both lower and higher concentrations (0.5% and 1%) compared with the control group (p < 0.05). In the meantime, there were no differences between the initial color of OG/CSG-coated fillets and the control group (p > 0.05), indicating OG/CSG coating did not affect the initial color of fish fillets. Based on sensory characteristics and microbial enumeration, the shelf-life of the control, 0.5% OG/CSG coated, and 1% OG/CSG coated fillets could be suggested as 5, 7, and 9 days, respectively. This study provides a scientific basis for the applicability of OG/CSG coating in fish preservation.