Just like the houses we live in,the ocean has several "floors" or layers.Different fish live on different layers and are neighbours,though not always friendly ones!
The ocean’s top layer is the sunlit zone(透光层).It goes down to around 200 meters below water.This layer is warm and bright.It is also home to most plants and fish.Many fish in this layer are streamlined,so they can quickly swim from danger and catch food.
The twilight zone(弱光层) is the next layer and is from about 200 to 600 meters below water.Almost no plants grow here.
Many animals in this zone swim up to the surface at night to feed,and move into deeper waters during the day.They also eat each other,so many of them have sharp teeth and very big mouths.
Many fish in this zone don’t have a streamlined body because they lie and wait for prey to come to them.
