Life under the surface of the sea is very different from on land. All the features of sea-dwelling creatures are organized in such a way as to enable them to live in water in the easiest way possible. Humans cannot see in water as well as do fish, because the human eye does not have the features that would allow it to attain sharp eyesight underwater. The human eye does not have a lens system such as that of the fish, and is not spherical and hard like that of a fish, so it does not have as sharp sight underwater as the fish. It cannot allow as precisely as fish do for foreshortening of distances in the water due to refraction, as it cannot estimate the refraction of light in water.

God has created every living being with the most suitable characteristics for the environment it inhabits. Creatures living under the sea constitute only a small part of the examples of God's artistry in creation. God has no partner in creation and everything is under His control.
 

There is no deity besides God. God – He is the Almighty, the All-Wise. (Surah Al ‘Imran, 62)