On Pokemon pearl what can you catch with emerald in Nintendo ds?

You can't use an Emerald save file to catch Pokémon in Pearl. The two games are different generations and incompatible with each other.

Here's why:

* Different Generations: Pokémon Pearl is a fourth-generation game (Diamond, Pearl, and Platinum), while Pokémon Emerald is a third-generation game (Ruby, Sapphire, and Emerald).

* Data Incompatibility: The save data formats and game mechanics are different between the two generations.

You can only transfer Pokémon from a third-generation game to a fourth-generation game using a specific method:

1. Pal Park: In Pokémon Diamond, Pearl, and Platinum, there is a location called Pal Park.

2. Transferring: You can transfer Pokémon from your Emerald save file to Pal Park using a special cable called the Nintendo DS Wi-Fi USB Connector.

3. Catching: You can then encounter and catch these transferred Pokémon in the Pal Park.

Note: This method only allows you to transfer Pokémon from Emerald to Pearl. It's not possible to transfer Pokémon from Pearl to Emerald or play Emerald on your DS using a Pearl save file.