In recent years, with the popularization and advancement of animal welfare concepts, its research scope has expanded from terrestrial animals to fish. Related issues have garnered increasing attention from government agencies, animal protection organizations, researchers, and aquaculture practitioners. Several factors may significantly impact fish welfare, including habitat conditions, aquaculture practices, fishing methods, market sales, and slaughter. Based on an overview of the concept and current progress of fish welfare research, this study summarizes the main factors affecting fish welfare, covering inter-individual interactions, environmental conditions, and production management. It further reviews relevant evaluation indicators for fish welfare, including behavioral indicators such as swimming, feeding, aggression, schooling, stereotyped behaviours, and escape; physiological and biochemical indicators such as neuroendocrine regulation, oxidative stress, immune and hematological responses; and other multidimensional comprehensive assessment methods. Finally, the study analyzes the limitations of current fish welfare research and prospects key areas for future research, aiming to provide a theoretical basis for establishing a standardized fish welfare assessment framework and promoting welfare-oriented healthy aquaculture practices.