Lewis McCartney is one of the main characters in the animated series, H2O: Mermaid Adventures.
Lewis McCartney is a little genius, the kind of guy who surfs the school program effortlessly and wraps up his homework before everyone else. As a result, he comes across as someone who makes no effort. His career dream is to become an inventor and researcher in robotics. Although he's top of the class, he's not a nerd and the butt of every joke of his classmates: quite the opposite. He's a good-looking boy, he knows how to send back a joke, and he's not afraid of Zane, although he finds him exasperating. Lewis is the only person outside the trio of our heroes who knows about the spell over them.
Lewis wears red short, a black singlet and black shoes. Unlike his live action counterpart is always is wearing glasses.