Yes, that would be due in part to him being a fire Pokemon. Of course not all fire types have the same coloration, but it's common for them to have a red-themed appearance of some sort.

[ He takes a moment to think. ]

But as to how to explain them... they're very common in my world. Just like regular animals, like dogs and cats and birds, but they're a little more special. Pokemon have many purposes. They are kept as pets and companions, some help people with their daily lives and work, or as a means of transportation. Most commonly though, they are used in battle against other individuals who have Pokemon of their own. We call these people "trainers".