Plecoglossus altivelis, commonly known as the Japanese eel, is a species of fish found primarily in the western Pacific Ocean. It is notable for its elongated body and can grow up to 1 meter in length. This species is anadromous, meaning it migrates from the ocean to freshwater rivers and streams to spawn. The Japanese eel is an important part of the aquatic ecosystem and is also a popular delicacy in Japanese cuisine. Due to overfishing and habitat loss, its population has declined, leading to conservation efforts aimed at protecting this unique species.