Answer:
Three little letters. A paradox to some. The worse that it is, the better it becomes.
I am mother and father, but never birth or nurse. I'm rarely still, but I never wander.
Long and slinky like a trout, never sings till it's guts come out.
Though I wander the earth, I am no longer here. I am pale and I chill everyone near. Who am I?
I am seen in the water. If seen in the sky, I am in the rainbow, a jay's feather, and lapis lazuli.
Iām grown from darkness but shine with a pale light. Very round I am and always a lady's delight.