lip locking is fairly normal for rams, though you want to keep an eye on it incase it gets too aggressive or injures one of them. Be sure that you definately have a differently sexed pair, and that you haven't been given two males by accident. You can reduce aggression by setting up different areas of the tank into defined territories, making sure you have plenty of caves for them to hide in, and ensuring that your substrate is small enough for them to dig in. Its fairly normal when they're settling into a new environment and sorting out dominance, though as i say keep an eye on them because sometimes it can go too far and you'll need to step in if that happens.
xxx