Discus sometimes wagging their head

[Cookie_discus]

As the title I always want to know how come my discus wagging their head sometimes? I also seen other discus doing this at my lfs.

[RogueDiscus]

The head wag, often accompanied by the whole body wagging or sort of shimmying is courting behavior. Showing off for a potential mate. Sometimes the wag seems more like a posturing or looking for a fight move. The female from one of my pairs will come to the front glass and do that like she's trying to chase me off if she's guarding fry.