I have both a flying and water type in my team, but I also have an empty space meant for a healer, that I never got. I want to keep five Pokemon on my team so it will be stronger, but I won't say no to gyrados if it's worth it My team: Flaffy Typhlosion Quayside Crobat heracross
And it's for a playthrough on heartgold
I say use it and replace Quagsire. Since it is for an in game play through, using attacking Pokemon is gonna be much better than defensive ones because of potion spamming. Also, intimidate would really help a lot especially against Dragonite lord, Lance. You don't need to have a healer since you can use potions during a battle and it always go first before the enemy attacks. Give it a moveset of dragon dance, waterfall, ice Fang and whatever you want the last move to be but make sure it's a physical attack