Fish and Worm by Dilip K Mehdiratta.  My daughter is at an age (she is three-and-a-half) where she does not know whether a worm and a fish can be friends or not. Sharing this story with her was like sharing truly wonderful moments. I am hoping she grows up to believe that it is not impossible for the unlikeliest of friendships to develop in the unlikeliest of situations. We read this book once every week to her.