The glass eel is the juvenile stage of the European eel and American eel. These transparent, elongated fish migrate from the ocean to freshwater rivers and estuaries, where they grow into adult eels. Glass eels are typically found in coastal waters and are known for their unique, see-through bodies, which help them evade predators. During their migration, glass eels undergo a transformation, gradually developing pigmentation as they mature into elvers. This stage is crucial for their survival, as they adapt to life in freshwater environments. Glass eels play an important role in aquatic ecosystems and are also sought after in commercial fisheries.