Jeff Spicoli learned: No me? No service!

In ancient depths, I silently roam, armored with scales as my timeless throne. By caviar's fame, I am known, a prehistoric swimmer in a river's flowing home.

Sometimes when you look at me, you see yourself, sometimes you see into me, I am often fresh but sometimes salty, Beneath my surface is another world of animals and plants, I am bounded all around by land

We are very little creatures; all of us have different features. One of us in glass is set; one of us you'll find in jet. Another you may see in tin, and a fourth is boxed within. If the fifth you should pursue, it can never fly from you. What are we?

In the park, I go back and I forth, From high in the air to the earth, A seat with a chain, Through sunshine and rain, I'm a ride of joy and mirth.