The Fourteenth Goldfish by Jennifer L. Holm (2014)
Ellie is now in middle school. Things have changed with her best friend, for instance. For another instance, she is always being told that she should find her passion (and her parents love the theater, so that should be her passion. Alas, it is not.) Suddenly, Ellie’s mother has to rescue her father (Ellie’s grandfather) from the police station. Well . . . her grandfather is a scientist (with an active fan club in Finland.) Has he figured out a secret of youth? He is suddenly 13 years old instead of 77! He moves in with Ellie and her mother. What happens next? Well, read the book to find out!
I enjoyed this book, and think nine and ten year old readers would really enjoy this story.