Angelfish fighting

only breeding angels lock lips like that. it's a courting ritual.
The lip locking is always occurs when they have been very aggressive and then after they lip lock one of them pushes the other to the side of the tank. Last night it happened four times in five minutes and one of the angels was going crazy. However, there is no real damage caused to either fish, i.e. no injuries at all.
 
that is exactly the behaviour exhibited by my angels a few days or a week before the female lays eggs.
 
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