I need help on Diamond

[kogeck]

I got up to the second gym, the Grass type gym, and I cannot beat it. I have the water-type starter Pokemon at a very high level, but I canno defeat the Gym.
Any tips?

[Oreo]

You should use Peck against the Grass-type because its Super Effective. Hopefully you taught it to your Piplup or Prinplup.

[Powdinet]

Dont use water moves, they will not effect them.
try using a fliyng poke.

[KingKitty]

Well it should know peck. but if it does not catch a starly and train untill its atleast level 18 and its will becomes a Starvia or get a kricketot as it proved quite helpful if it knows furry cutter as mine was able to take out both her cherubi and her turtwig.

[digitalree]

i beat her she is easy grass does not like fire water is not very affective since you picked prinpup- you have to know flying type moves from a starly or your prinpup i hope this help flying=ow
fire=ow