Answer:
My first is in fish but no in snail. My second is in rabbit but no in tail. My third is in up but not in down. My fourth is in tiara but not in crown. My fifth is in tree you plainly see. My whole a food for you and me.
So cold, damp and dark this place. To stay you would refrain, yet those who occupy this place do never complain.
Forward Iām heavy, but backwards Iām not.
The more of them you take, the more you leave behind. What are they?
I have legs but walk not, a strong back but work not. Two good arms but reach not. A seat but sit and tarry not.
You use it between your head and your toes, the more it works the thinner it grows.