Answer:
You write on me and secrets I can keep. In places never seen. I spin like a top. Though stiff as a board I'm often described like a mop.
What is put on a table cut but never eaten?
I work when I play and play when I work
I am the kind of fish that chases a mouse.
By Moon or by Sun I shall be found. Yet I am undone if there's no light around.
It has no top or bottom, but it can hold flesh, bones, and blood all at the same time.