Euphausiidae, commonly known as krill, are small, shrimp-like crustaceans found in oceans worldwide. They play a crucial role in marine ecosystems, serving as a primary food source for various species, including whales, seals, and fish. Krill are characterized by their transparent bodies and can range in size from 1 to 6 centimeters. These organisms thrive in cold waters, particularly in the Southern Ocean surrounding Antarctica. Euphausiidae are known for their swarming behavior, forming large groups that can number in the millions. Their abundance and nutritional value make them essential for maintaining the balance of marine food webs.