Answer:
Long and slinky like a trout, never sings till it's guts come out.
What is round as a dishpan, deep as a tub, and still the oceans couldn't fill it up?
I am never quite what I appear to be. Straight-forward I seem, but it's only skin deep. For mystery most often lies beneath my simple speech. Sharpen your wits, open your eyes, look beyond my exteriors, read me backwards, forwards, upside down. Think and answer the question...
A mile from end to end, yet as close to as a friend. A precious commodity, freely given. Seen on the dead and on the living. Found on the rich, poor, short and tall, but shared among children most of all.
I'm full of holes, yet I'm full of water.
Iām grown from darkness but shine with a pale light. Very round I am and always a lady's delight.