>>47069793oh we are playing this game now? Ok retard.
All mons that are blue are now water type because gyarados is blue. Fish need their mouth open to breathe, that's how gills work. If you can't cope with the fact that this game was made in japan and how things don't line up with western culture I honestly have no clue how you even made it this far liking pokemon. Gyarados is a based on a fish kite, they are shown all over japan on childrens day, a tradition dating back to mid 1900s, this is why gyarados is water flying. It was even referenced in the anime, personally i don't see the anime as canon but it still appears in the franchise
If you want we can go into prerelease pokemon, Originally gyarados looked like a giant leach. Or the fact that gyarados could be a reference to a giant winged eel that causes storms from african folk lore.