Will it change colour or will it remain the same as a regular pikachu? Just curious
Pikachu-coloured Pichu is just, in fact, a Shiny Pichu with some special coding associated with it to activate the HGSS Notched-Ear Pichu. So it will evolve into a Shiny Pikachu, and then a Shiny Raichu.
Hope I helped. :) Source