Dorothy is not a Muppet, but is portrayed by a real, live goldfish (most likely, multiple goldfish over the course of the series). When represented in books or toys, Dorothy often has a feminine appearance, including big eyelashes. This is also not typical for your average goldfish. First introduced on "Elmo's World" in 1998, Dorothy has also made appearances in the main Sesame Street storyline, beginning in 2000, thus demonstrating her independent existence outside of Elmo's imagination. Episodes in which Dorothy has played a key role in the main street action include: