Electric and Grass.
Water Pokemon are weak against Electric and Grass type moves.
Water
Ligtning type moves, and grass type moves are super effective against water.
Water-type Pokemon are weak against Electric and Grass-type moves.
Water-type Pokemon are weak against Grass and Electric-type moves.
Ground type moves, rock type moves and water type moves are super-effective against fire type pokemon.
Water type moves and Grass type moves. Electric moves will have no effect. Flying types and Pokemon with levitate ability are good as ground-type moves have no effect against them.
For his Dragonites (x3), have Ice-Type Pokemon at hand. For Charizard, have a Water-Type Pokemon. For his Gyarados, have a Electric-Type Pokemon. For his Aerodactyl, have a Water-Type as well. The 2nd time you face him: Use Ice or Electric Moves or Pokemon against his Salamence. Use Ice or Water Moves or Pokemon against his Garchomp. Use Ice or Electric Moves or Pokemon against his Altaria. Otherwise, he has a Dragonite, Charizard, and Gyarados. Just read above to know how to handle them.
Water/Ice type pokemon are weak against rock, electric, fighting, and grass type moves
See, electric type moves are effective against water Pokemon. Thunder or Thunderbolt are powerful attacks very effective against water Pokemon such as kingdra. ACTUALLY, since Kingdra is a dragon type too, electric type moves are just normally effective. Dragon type is super effective against Kingdra. But then Kingdra would be supereffective against you too!
Depends. Water is not very effective against Dragon types. However it is possible for most water Pokemon to learn ice type moves and these will be super effective. Good luck!
Graveler is a ground and rock type pokemon, its weak against grass type moves, water type moves, steel type moves, ground type moves and ice type moves.