Which Pokémon Game is Best for a Mono-Type Water Team?

As the MOST common Pokémon type that leaves Water with a LOT of potential for pretty much any region out there, (certainly much more than the other two Starter Types) so it might be a bit hard to narrow down where it would be best to use these aquatic creatures! Largely coming down to the makeup of the regions, and availability of said Pokémon in the course of your journey, so let's see where Sea-faring Pokémon float!