http://news.yahoo.com/blogs/oddnews/rescued--puppy--actually-not-a-puppy-at-all-172906379.html?vp=1
All you have to do is look at its feet and you can tell that.
I'm doubting it's a fox either.
I don't really have any other thoughts except that an otter sounded more logical to me. Not even puppies are as cute as otters, and this guy is extremely cute.
Plus, his ears and paws are right.