Quick thought/question seeing as this takes place in Hoenn

Water Pokemon and battling in water. With the approach we're taking, I'm assuming it'll be more like the anime? Should we expect that sending a Goldeen out to battle on land will just end up with it flopping around uselessly? Will trainers with no Pokemon that are good swimmers be at a serious disadvantage on the eastern half of the map? Lol this is the kind of thing that comes to mind while I'm working