Llyn Dulyn is a small natural reservoir bound by the high steepy rocks of Gardnedd Uchaf and Foel Grach on the edge of the Carneddau mountains, in Snowdonia, North Wales. It has a surface of 13 ha (33 acres) and its maximum depth reaches 58 m ( 189 feet). It has a dam, which was built in 1881, but is has been altered a couple of times since. The reservoir supplies water for the city of Llandudno. Arctic char can be found here. It is very black and its fish are deformed and unsightly, with large heads and small bodies.