Originally Posted by Virto
White spots around lips are often caused by columnaris. These fish are new - did you add them to a tank with other fish that you already had? There's a good chance that the others will develop symptoms in short order.
Yup I'd have to say its columnaris. The behavior you are describing along with the white mouth is a dead give away.
Virto is right about the other fish getting it. Nasty nasty illness