With the wide expansion of the aquaculture sector, aquatic organisms are exposed to an increasing number of environmental stressors which affect their behavior, physiology and eventually their health and performance. As fish is an ectotherm, water temperature is one of the most important abiotic factors which affect the growth, metabolism, immunity and survival of fish. Each fish species is characterized by an ideal range of temperature in which they show their maximum growth and performance. While a temperature above the physiological range of a fish species triggers a stress response that can negatively impact the fish immune function. The induced adverse effects of suboptimal temperature attracted the attention of researchers to find significant approaches which could help in protecting the fish reared under these environmental changes. One of the strategies which could help in improving fish immunity is the utilization of probiotics. Thus, this review highlights the benefits of probiotic-rich diets in strengthening the immunological, pharmacological, and protective defenses against stress induced by water temperature changes on fish welfare.