I think the problem here is more about composition...the dog is like a big arrow pointing nowhere, I think you should rearrange things so that he is pointing to the moon, or there are some elements pointing to him, that way you'd understand by context that he's a dog, it'd also help if the dog's background was cleaner than those buildings, cause the dog is pretty dirty already.
you might also want to alter his face, it's not really very face-like :p