Krill are nutrient-rich crustaceans widely recognized for their potential in aquaculture nutrition. They contain high-quality protein, essential amino acids, phospholipids, omega-3 fatty acids, minerals, and astaxanthin, which contribute to improved growth, health, and feed utilization in aquatic animals. Various krill-derived products, including krill meal, krill oil, krill hydrolysate, freeze-dried krill, and krill protein concentrate, are increasingly used as functional ingredients in aquafeeds. Their bioactive compounds enhance feed palatability, osmoregulation, stress tolerance, and overall performance of cultured species. This article highlights the nutritional composition of krill and the applications of krill-based products in aquaculture.