The final rodent in our infestation is Pacha. He's smaller and less adventurous than his brother, Kuzco, but is a bit high-strung. Apart from that, the only way to tell them apart is Pacha has ears of a lighter colour.
Both Pacha and Kuzco were, it's true, named for the lead characters in The Emperor's New Groove, one of our favourite movies. We really need a guinea pig named Kronk.