Koi boy is the first book of my phun pun series. what is a phun pun? A phun pun is a play on words and the stories themes are the "morals of the story." Koi boy is the nickname that young Michael gets from his father when Michael learns that the Koi pond he found and loves is being replaced with a hospital. By realizing and accepting this, his Dad builds him his own Koi pond and tells him "I love you my Koi boy."