Grass beats Water.
Deku beats Zora.
Pokémon Logic! :xd:
Oh god, so this. :yes:
Zora Warrior (TP)
But seriously... Regarding who I think would win, I'd say the Zora hands down. They have major advantage over the Deku, seeing as they are highly adept in several forms of combat, as shown in at least three games in the series (not counting the supposed "river Zora"). In
Majora's Mask (for example), the character Mikau, is implied to have had some skill in the art of combat. Even before his spirit was transferred to Link via the Zora's mask, he was able to survive an attack from enemies while in retrieval of Lulu's eggs long enough for Link to find him. Surely, said skills serve as a testament to the Zora's fighting ability. Not to discount their superior aquatic athleticism... (also, see Zora warriors in TP)
The Deku on the other hand are adept at long-ranged combat, which might come in handy at
Deku Scub (OoT)
distance, but in close-quarters they wouldn't stand a chance against the Zora. They have very little at their disposal as far as combat and physical strength goes. I mean, much of their species lack the proper appendages to wield a weapon, let alone throw a punch. Not to mention the height and speed disadvantage that comes with being a small plant/wood-based creature. Shooting Deku nuts (and in some cases, bubbles) can only go so far.
It all boils down to the fact that the Zora are more humanoid in physical appearance - having opposable thumbs and all - and as such, are more versatile in combat over the Deku, whom lack many of said qualities. Above all else, the Deku seem to be a peace-loving, docile species overall - evasive even, as seen with Business Scrubs and Mad Scrubs. While, the Zora, albeit peace-loving to a degree, can be quite combative when the need arises...