The ZhuZhus theme song

 The "The ZhuZhus theme song" is composed by Jesse Colburn and Aaron Verdonk, and is featured in every episode.

1 (Polly and the ZhuZhu Pets)
Before the name change, this theme was used from episode 1a to episode 7b.

1 (The ZhuZhus)
After the name change, this theme was used from episode 8a to present day.