Maybe you're thinking of the Elves in Elder Scrolls who are solely carnivores?
Correct me if I'm wrong, but aren't just Bosmer strictly carnivorous, and only for cultural/religious reasons? I don't think I've heard about all mer being carnivores (though perhaps I'm poorly informed).
I'm hardly an expert on Elder Scrolls lore but yes, it's the Wood Elves" in the Emerald Forest who strictly eat meat, I don;t know if it's because they can't metabolize anything else or if it's a "super-environmentalist" cultural/religious thing, I think both are cool.
The Green Pact, also known as the Treaty of Frond and Leaf, is a strict code upheld by many of the Bosmer of Valenwood. It is said to have guided their existence since the beginning of the "great story". Its rules are clear. Do not harm the forests of Valenwood. Do not eat anything made from plant life. Eat only meat. When enemies are conquered, their meat must be eaten, not left to rot. Do not kill wastefully. Do not take on the shape of beasts.
More on topic: I like how Skyrim actually makes elves look "alien". They don't look great, but that's more a matter of execution rather than design, I think. (And of course TES games vary wildly with race depictions...) Oblivion Character Overhaul mod does a pretty good job at that. (Erring on the side of "pretty", but elves still look distinct.)