banggai w/swollen lip

[Clare7]

I have a banggai cardinal whose lower lip is protuding. I know this is somewhat common in banggai cardinals but what is the cause/treatment.
Thanks in advance.

[miracles38]

Mine did that when I moved them into a glass tank that showed their reflection. It healed on its own. Although, my female still has the lower lip protruding it doesn't seem to interfere with eating or making babies! This happened over a year ago.