none. you take heart scales to the move tutor. i don't remember where he is though. i think the town next to the volcanic ash.
Heart Scale does not evolve any Pokemon. You trade it to a maniac who will make Pokemon remember moves. In black and white, the maniac is in Mistralton city.
You can evolve Seadra by trading it with the Dragon Scale
seadra
no but he/her holds a heart scale
Well, Dragon Scale evolve some Pokemon like Seadra.But you have to let it hold and trade it to evolve.
The best place to evolve a Pokemon in Pokemon Heart Gold is at Mt. Silver.
Farfetch'd is a Pokemon that does not evolve.
It evolves from Horsea starting at level 32, and evolves into Kingdra when traded holding a Dragon Scale.
You can evolve Seadra by giving it a Dragon Scale and then trade it. Seadra will then evolve into Kingdra.
you use it for the move maniac who reteaches your Pokemon a moves for one heart scale
Farfetch'd does not evolve in Pokemon HeartGold. Sorry! :)
Seadra to evolve it into a Kingdra.