Pokémon Diamond Version, Pearl Version, and Platinum Version - Trade and Migration Notes
For compatibility reasons, a Shaymin in the Sky Forme, a Giratina in the Origin Forme, a Spiky-Eared Pichu, a Rotom not in its normal form, and a Pokémon holding a Griseous Orb can’t be traded. In addition, a Pokémon with a Classic Ribbon can’t be deposited to the Global Trade Station, nor can Eggs.
A Pokémon from a Korean language version can’t be traded via the Union Room from a Korean-language game to a non-Korean language game. This is because non-Korean language games don’t include Korean characters. This restriction is most relevant for Pokémon with a Classic Ribbon.
A Pokémon with one or more of the moves Cut, Dive, Flash, Fly, Rock Smash, Strength, Surf, and Waterfall can’t migrate.
A Pokémon migrated from a GBA game retains its base stats (EVs) and stats, and is not considered to be caught with a Park Ball.