Ikedako Lake in Kagoshima Prefecture is the largest caldera lake in Kyushu. It was shaped through volcanic activity and has a circumference of 15 kilometers, stretching to a depth of 233 meters at its deepest point. The lake water sinks into an indigo blue, and Mt. Kaimon-dake, also called Satsuma Fuji, can also be seen from here. The lake is also famous for the giant mottled eels that inhabit it, which are designated as a protected species of Ibusuki City. Flowers decorate the shores of the lake during each of the four seasons, so visitors can enjoy the beautiful scenery throughout the whole year. January is particularly popular, when the field mustard flowers are in full bloom: many people visit to jog or cycle on a course known as the "field mustard marathon." Visitors can also have some fun searching for Issie, the mysterious creature that is said to inhabit the lake.