Fish is one of the most perishable foods, highly susceptible to microbial and chemical spoilage due to its biochemical composition. Quality assurance (QA) in fisheries, through systems like HACCP, GMP, and ISO standards, is essential for ensuring safety, extending shelf life, and maintaining consumer trust. Microbial risks include spoilage organisms such as Pseudomonas and Shewanella, and pathogens like Salmonella, Vibrio, and Listeria, while chemical and sensory metrics such as TVB-N, TMA, histamine, and odour or texture serve as key indicators of quality. Shelf-life determination combines empirical testing and predictive microbiology, with AI and machine learning enhancing accuracy. Quality failures can cause foodborne outbreaks, recalls, and economic losses, with scombrotoxin and ciguatoxin being major culprits. Emerging trends like smart packaging, AI-driven detection, and blockchainenabled traceability are reshaping QA practices. Ultimately, consumer handling, storage, and respect for expiry dates remain critical for safeguarding fish quality and protecting public health.