Turritopsis dohrnii, known as the 'immortal jellyfish,' inhabits the Mediterranean Sea and Japan. It is renowned for its ability to revert to its juvenile form after reaching maturity, effectively bypassing death. This species is small, translucent, and bell-shaped, playing a role in the marine ecosystem as both predator and prey.

Turritopsis dohrnii, commonly known as the 'immortal jellyfish,' is native to the Mediterranean Sea. It has also been found in other parts of the world, such as the Atlantic Ocean, the Pacific Ocean, and the Caribbean Sea, suggesting a broad distribution due to ocean currents and possibly human-mediated transport.

This species typically inhabits warm, temperate marine environments. It is commonly found at depths where the temperature ranges from 14 to 25 degrees Celsius, though it can survive in a wide range of temperatures due to its unique regenerative capabilities.

Turritopsis dohrnii is part of the pelagic zone, primarily dwelling in the open sea. It plays a role in the marine food web as both predator and prey. As a cnidarian, it preys on small planktonic organisms using its tentacles. Its remarkable ability to revert to its juvenile form allows it to survive environmental stresses, making it a unique subject of study in marine biology.