Who am I?

another childhood poem :) I think i was about eight when I wrote this...

I am a creature watch how I glide,

Twisting and turning under the tide,

Watch how I fly my oh my,

I am more graceful than a butterfly.

Watch all the fish swimming by,

Oh how I wish I could be in the sky!

Oh how I swim, quiet like mice,

But now it is time to slide on the ice.

Author's Note

Who am I???
What do you think of it?