Vitamin D₃ is an essential vitamin for aquatic animals and functions to maintain normal growth, development, and nutritional metabolism. Aquatic animals barely synthesize vitamin D₃ in the body. Instead, they obtain vitamin D₃ mainly from feed. To gain deep knowledge concerning mechanisms by which vitamin D₃ regulates carbohydrate and lipid metabolism in aquatic animals, we summarized dietary vitamin D₃ requirement and its influencing factors, and illustrated vitamin D₃ absorption, transport, metabolism and regulatory mechanisms, and the mechanism of vitamin D₃ regulating carbohydrate and lipid metabolism in aquatic animals. At present, studies are very limited on nutrition physiology, metabolism and regulation on carbohydrate and lipid metabolism by vitamin D₃ in aquatic animals, and many important scientific questions remain unresolved. In the future, it will be necessary to set up a unified standard evaluating “dietary vitamin D₃ requirement of aquatic animals” and to target studies concerning mechanisms regulating carbohydrate and lipid metabolism in aquatic animals, which will provide references for precise regulation of vitamin D₃ nutrition physiology in aquatic animals.