<![CDATA[Fish sperm cryopreservation is an important reproductive technology for supporting hatchery production, broodstock management, and the conservation of fish genetic resources. However, cooling, freezing, storage, and thawing may cause cellular damage, commonly referred to as cryoinjury, through osmotic imbalance, ice crystal formation, mitochondrial dysfunction, and increased production of reactive oxygen species (ROS). Excessive ROS accumulation that exceeds the capacity of antioxidant defense systems can induce oxidative stress and lipid peroxidation, thereby reducing post-thaw sperm quality and fertilization capacity. This article aims to review the mechanisms of oxidative stress during fish sperm cryopreservation, identify the types and mechanisms of action of antioxidants, and evaluate their effectiveness based on studies involving various freshwater and marine fish species. The review was conducted by examining literature relevant to fish sperm cryopreservation or preservation, oxidative mechanisms, and antioxidant supplementation. The selected literature was analyzed descriptively and comparatively according to fish species, antioxidant type, concentration, extender formulation, and the sperm quality parameters assessed. The synthesis indicates that antioxidants, whether derived from endogenous defense systems or introduced as exogenous supplements, may help maintain sperm quality by regulating ROS levels and reducing oxidative damage. Various compounds, including vitamins C and E, glutathione, melatonin, and other antioxidants, have been investigated, with varying responses in sperm motility, viability, membrane integrity, lipid peroxidation, and other reproductive parameters. However, antioxidant effectiveness is not universal, as it depends on fish species, compound type and concentration, extender and cryoprotectant composition, and freezing and thawing conditions. Therefore, optimizing antioxidant formulations and concentrations, together with the integrated assessment of multiple biological parameters, is necessary to improve the success of fish sperm cryopreservation.]]>
