My Big Fat Zombie Goldfish #6: Jurassic Carp book by Mo O'Hara

Frankie was a completely normal pet goldfish . . . until Tom's evil-scientist big brother, Mark, tried to murder him with toxic gunge! Luckily Tom and his best friend Pradeep shocked Frankie back to life with a battery, and he's been their zombie-fishy friend ever since.

At a medieval re-enactment event, some-fin very weird starts going on. One of the knights is acting very suspiciously . . . and Tom is sure he's seen his evil big brother's vampire kitten lurking around. Can Pradeep and Tom work out what Mark is up to without revealing Frankie's secret zombie skills?

In story two, a Jurassic carp fossil is found underneath the school playground. Can Frankie, Tom and Pradeep stop Mark's evil plan before his BEASTLY secret gets out?