Glaucus atlanticus, also known as the Blue Dragon, is a small, pelagic sea slug found in warm ocean waters. It floats upside down on the ocean's surface, using the wind and currents to travel. Notable for its striking blue and silver coloration, it preys on venomous jellyfish, storing their stinging cells for its own defense.

Glaucus atlanticus, commonly known as the blue dragon, is found in temperate and tropical oceanic waters around the world. Its distribution includes the Atlantic, Pacific, and Indian Oceans. It is commonly found off the coasts of South Africa, Europe, Australia, and Mozambique.

Glaucus atlanticus inhabits the open ocean, particularly in warmer waters. It is typically found floating with the aid of a gas-filled sac in its stomach, which allows it to drift on the ocean surface. The species thrives in regions with a surface temperature range between 18°C and 24°C.

As a pelagic species, Glaucus atlanticus occupies the surface layer of the ocean, where it feeds on other pelagic organisms such as Portuguese man o' war and other siphonophores. It is a specialized predator, known for its unique ability to store prey's venom within its own tissues for defense against predators. This adaptation allows it to occupy a niche as both predator and prey in the marine ecosystem.