Fish Jump Out of Water

When exploring near a tropical ocean i noticed shoals of fish jumpin around near/on the surface of the water.

What I expected to happen was: The fish would stay underwater, and never reach the surface.

What I saw: the fish would come to the surface and be visible above the water.

Steps to reproduce:

1. Find a tropical ocean full of tropical fish
2. Wait for one to come to the surface
3. Notice that it comes above the water