Answer:
Long and slinky like a trout, never sings till it's guts come out.
Come up and let us go. Go down and here we stay.
Though blind as well, can lead the blind well.
The more of it there is, the less you see.
You throw me out when you want to use me and you take me in when you don't want to use me. Who am I?
What is so fragile that saying its name breaks it?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?