In New Leaf and Pocket Camp, Fuchsia wears the polka dot tee. Fuchsia is also shown in the polka dot tee on her Amiibo card. In New Horizons, Fuchsia's default outfit is the zigzag dress. I think that Fuchsia looks better in dark clothing; the polka dot tee has a black base to it, whereas the zigzag dress is primarily blue and purple. Fuchsia is already so colorful so she doesn't need more color in her clothing. If I were to invite Fuchsia to my island, I would gift her something black or dark brown to change into.