"Little Fish sees Shark and Octopus behind the reeds, and then notices someone is inside the seashell. It’s Crab, who doesn’t like to be disturbed! Little Fish wants to join the sea jellies as they bob along in the water. Then Little Fish sees Whale blowing bubbles and blows bubbles, too. And at the end of the day, Little Fish returns home to sleep behind a large seashell."--publisher's website.

The pout-pout fish believes he only knows how to frown, even though many of his friends suggest ways to change his expression, until one day a fish comes along that shows him otherwise.

Alejandro quiere averiguar más sobre el cuaderno de lo monstruos. ¿Qué quiere decir P.M.S.S.? ¿Por qué encontró él el cuaderno? Pero prmero debe enfrentarse a más monstruos. ¡Hay lombrices por todas partes! ¡Solo Alejandro puede salvar a Montalbán!