Mitigation strategies against cold stress in tropical fish – a review

Cold stress is a significant threat to aquaculture, affecting fish growth, survival, and productivity. Despite its importance, there is a research gap in understanding the mechanisms of cold stress tolerance in aquatic animals and developing effective solutions. This review provides an overview of the different effects of low water temperature on the biological processes of tropical fish. It tackles the physiological changes, such as variations in digestive enzymes, lipid composition, fatty acid profile, and gene expression, that affect fish performance when fish are exposed to low temperatures. This review also showcases the different methods used to enhance the tolerance of fish species to low thermal stressors. These methods include physical barriers, reduced feeding frequency, and use of biofloc and dietary functional feeds. These methods also serve as effective mitigating strategies to combat poor growth, disease outbreak, and mortality in cultured tropical species in overwintering. Thus, the current review article concludes and recommends different directions to cope with the cold stress challenge, such as investigating molecular mechanisms, developing genetic markers, improving water management, investigating the role of nutrition in enhancing cold stress tolerance, selective breeding, developing breeding programs for cold-tolerant aquatics, and monitoring and prediction. Among the many strategies, the present review article highlights the role of utilizing feed additives with functional roles, which seems to be very effective, although sufficient studies and data are currently limited.