Fish is Fish is a children's book by Leo Lionni about the friendship between a minnow and a tadpole, exploring themes of imagination, friendship, and perspective. When the tadpole grows legs and becomes a frog, he leaves the pond to see the world, returning to describe birds, cows, and people to his fish friend, who imagines them as fantastical "bird-fish" and "cow-fish". The fish's attempt to see the world for himself ends in danger, but the frog saves him, highlighting their bond and the idea that different creatures experience the world differently..