Each fish species has a preferred water layer where it spends most of its time: near the surface, in the middle, or near the bottom.
Each fish species has a preferred water layer where it spends most of its time: near the surface, in the middle, or near the bottom.
每一种鱼都有偏好的水层，它们大部分时间都会呆在那儿：接近水面的上层水区、中层水区、或是接近水底的底层水区。