Answer:
Long and slinky like a trout, never sings till it's guts come out.
You can always see it, but it's too far away to touch. Mountains rest on it, and at sea it surrounds you. What is it?
No matter how little or how much you use me, you change me every month.
What is weightless but it needs two person to hold it?
In we go, out we go. All around and in a row. Always, always steady flow. When we'll stop, you'll never known. In we go, out we go.
Iām grown from darkness but shine with a pale light. Very round I am and always a lady's delight.