The Fourteenth Goldfish Books in Order

The Fourteenth Goldfish books take a classic middle grade question, what if science could change everything, and turn it into something both funny and personal. The series follows Ellie, a practical, curious girl whose life gets upended when a grumpy teenage boy shows up and seems to be her grandfather Melvin in a much younger body.

That is where the trouble starts.

Grandpa Melvin is a scientist who has spent his life chasing big ideas, especially the dream of immortality. In The Fourteenth Goldfish, that obsession becomes impossible to ignore when one of his experiments appears to work. For Ellie, the science-fiction setup is only half the story. She is also dealing with ordinary changes, shifting friendships, school, and the weirdness of suddenly having her grandfather around in a form nobody else quite understands.

The books are fun because Holm treats science as both exciting and a little unruly. Ellie and Melvin talk about famous scientists, experiments, discovery, and possibility, but the series never turns into a classroom lecture. Instead, it asks kid-sized versions of bigger questions. Just because you can do something, should you? What happens when curiosity outruns wisdom? Is living longer the same as living better?

The sequel, The Third Mushroom, keeps Ellie and Melvin together and raises the stakes through a science fair project and a more urgent search for the key to youth. When Ellie's cat gets sick, the questions stop being theoretical. That gives the second book a little more emotional pull, while keeping the same lively mix of humor, school life, and big scientific ideas.

Ellie is a good guide through all this because she is not dazzled by everything. She is thoughtful, skeptical, and often the most grounded person in the room. Melvin, meanwhile, is funny precisely because he is brilliant and childish at the same time. Their relationship gives the series its real warmth.

The tone sits in a nice middle space. These are science-forward books, but not hard science fiction. They are family stories with a speculative twist, and they work well for readers who want something smart without losing the emotional part.

If you want middle grade that mixes STEM ideas with family comedy and real heart, The Fourteenth Goldfish is a strong pick. It is a series about discovery, but also about accepting change, valuing the time you have, and remembering that even the wildest experiment still lands in ordinary human life.