How do you beat the 3rd gym in Pokemon platinum?

The third gym is Fantina's gym and she has ghost Pokemon. As long as you have a Pokemon with bite or crunch, it should do okay. Otherwise, you could just use a Staravia. Since it is part normal type, all ghost type moves are effectless. One thing to look out for is curse. It will take out 1/4 of your max hp EVERY TURN! Bibarel might do good.