《后汉书·列传·乌桓鲜卑列传》
鲜卑人口日益增多，农业、畜牧和射猎满足不了吃饭，檀石槐于是亲自巡视，他见到乌侯塞水有几百里宽阔，水不流动，水中有鱼，但没办法得到鱼。
种众日多，田畜射猎不足给食，檀石槐乃自徇行，见乌集秦水广从数百里，水停不流，其中有鱼，不能得之。
The Xianbei population grew day by day, and agriculture, animal husbandry, and hunting could not meet the need for food, so Tanshihuai inspected it in person. He saw that the Wuhou Sai water was hundreds of miles wide, the water did not flow, and there were fish in the water, but there was no way to get the fish.