Angelfish behaviour

Hi guys and gals , recently I bought 4 platinum angels for my 4ft , now the last time I bought angels was in high school many years ago and prob didn't pay as much attention to them as I do now , they about 6-7cm top to bottom and they have some seriously interesting behaviour, I seem to have a single dominant fish which is the boss and will every now and then chase the others around , 2 of the other fish seem to display a submissive before mostly by lowering their heads down as the dominant one approaches them , the other one doesn't submit to this dominant fish though and will generally turn and face it , the 2 fish then generally nip at each others mouth and I have also seen them sort of a shake with their bodies in front of each other, the strange thing is the one that will generally face off with the dominant fish doesn't chase the other two like the dominant one does, this is completely new to me and I must admit I am enjoying the heck out of watching this social behaviour it is absolutely fascinating , so anyway do you guys have any idea as to what all this displaying means and if it is true that in a social group there will be a single dominant fish?

 

Basic pairing, but, sound like you have more males than females. As they get more involved, they will grip each others by the mouth to test "strength".