The Brachymystax lenok is a freshwater fish which lives in water less than 20℃.It has irregular small red spots on a silverish-white ground.
During spwaning time, the whole body becomes red and dorsal and pectoral fins have rainbowlike luster.
It ususally feeds on larvae of insect in water and small fishes.
When Yeonhwa mine was developed in Daehyeon-ri, water was contanimated by waste water.
This made some parts of Baekcheon Valley impossible for brachymystax lenok to live in it.
In addition to this, the increase of miners made some parts of protection areas mine villages.
This deteriorated the situation a lot more.
The places where brachymystax lenok spawns and spends winter months were covered with earth and sands.
So since 1965, this fish couldn't be seen in this area.
In 1986, about 100 Brachymystax lenok were caught in Jangchon-ri, Nae-myeon, Hongcheon-gun and the half were brought to the pond in Daehyeonsa Temple and the rest were set free in the Daehyeonri Valley.Brachymystax lenok breeding place in Seokpo-myeon, Bonghwa is the southernmost part in the world where this rare fish can live.
Since overfishing is decreasing this fish, it is designated and protected as a natural monument.