Answer:
Long and slinky like a trout, never sings till it's guts come out.
I can be written, I can be spoken, I can be exposed, I can be broken.
The more of it there is, the less you see.
Long and think, red within, with a nail at the end.
I cannot be felt, seen or touched. Yet I can be found in everybody. My existence is always in debate. Yet I have my own style of music.
What never gets any wetter no matter how hard it rains?