The Fleas share a pale, light grayish aquamarine skin with teal hair with a white robe with a violet belt on the waist. They have eyes with white pupils and black sclera, and the older ones have bags underneath their eyes. The only difference between male and female, physically wise, are a single eyelash in the eyes of the girls.
The fleas originally lived in the Ballzeria system, formelly formed with nine planets, including Ballzeria 9, but it were destroyed by the space dog known as Buster. While on their way to fly eternally in outer space, Wander managed to get them a brand new home in the least likely of places: Buster's fur.