This is my first time having a purebred rat terrier. The last one was rat terrier/shih-tzu. My puppy is 10 weeks old and has a soft fluffy coat. I was wondering when his sleek shiny coat will come in. Also, if his ears will be erect when can i expect them to stand up (I'm kinda liking the button ears, honestly ;)
In general Rat Terriers are smooth coated breeds, so you can probably expect that "puppy coat" to turn into a sleek smooth coat. I have seen a few retain that "puppy fluff" though. As for the ears, some never stand up erect, but if yours do, they should be up by the time your pup reaches 10 months of age.
All puppies have a soft, fluffy coat that they will lose or shed when they grow in their adult coat by about 8 months to a year of age. However, some adult dogs end up growing in a fluffy coat! I've never seen a rat terrier that didn't have a smooth, shorter coat, but if your dog is a mix-breed, it's certainly possible that he got his coat from the other parent!