Nothing is official, and no one at Warner Bros. is going to say anything until they're damn well ready to, but Aquaman is expected to show up somewhere in the studio's massive slate of DC movies. As for the character himself, outside of comic book circles, it's safe to say the general public doesn't really know much about him, except that Vinnie Chase had arc around starring in a James Cameron-directed "Aquaman" in "Entourage." But when the Detroit (where "Batman v. Superman: Dawn Of Justice" is shooting) based radio station The Ticket apparently "disparaged" the character, Snyder himself called in.
"I don’t want to give anything away about the movie or anything like that but Aquaman has some cool abilities," Snyder said (and yes, Slashfilm confirmed it was really the filmmaker). "People are like, 'Oh what? Does he talk to animals? Cause that seems like what he does. Or fish?' The cool thing with Aquaman is he’s Triton so you have to realize that could cut the flesh of Superman if they came in contact. That’s a thing that’s in the canon. He’s super strong cause of course he can exist at these super deep depths so when he comes up here he’s crazy strong. Anyway, not to say he’s in my movie or anything like that but he has the potential to be bad ass, that’s all I’m saying."
So, take all that for what you will, and in summary: Aquaman is cool, and Snyder doesn't want to spoil 'Dawn Of Justice,' so he won't say whether he's in the movie or not (though with Jason Momoa cast and apparently spotted in Detroit, all signs point to some kind of appearance — or maybe he'll show up in "Justice League," which is shooting back-to-back with 'Batman v. Superman').
You can listen to Snyder's defense over at CBS Detroit.