grass types
Fire type is super afective, Water is also very good.
Electric
no Actually yes. There are some Pokemon (dewgong for example) that are water and ice and ice beats water.
With a water type pokemon.
It depends on what Pokemon you get. if you get a water type ,he'll get a grass type.
fishing or surfing
With Water-type or Flying-type
It's the water type, Milotic.
Pokemon 139 in Pokemon Pearl is Omastar, a Water/Rock-type Pokemon. It is the evolved form of Omanyte, and it has strong defensive stats and access to a variety of water and rock-type moves.
First see what Pokemon they have then remember the Pokemon and the type they are. Get the types that's good against the Pokemon they have and train them to level 100. Water beats Fire Water beats Rock Fire beats Grass Fire beats Ice Fire beats some Bug Grass beats Water Grass beats Rock Ground beats Fire Ground beats some Bug Psychic beats ghost ... ... ...
electric and grass types
you get a .pokemon called Turtwig grass type, chimchar the fire type and piplup the water type