Anguilla Anguilla, commonly known as the European eel, is a species of eel found in both freshwater and saltwater environments. It is known for its long, slender body and can grow up to 1.5 meters in length. This species is notable for its complex life cycle, which includes a migration from freshwater rivers to the Sargasso Sea for spawning. The European eel is a catadromous fish, meaning it spends most of its life in freshwater but returns to the ocean to reproduce. Overfishing, habitat loss, and pollution have led to a decline in its population, resulting in its classification as an endangered species. Conservation efforts are underway to protect this unique fish.