Mine always do funny "mating dances". Is it possible they've laid eggs and the eggs were just eaten by my crustaceans or other fish? The one also became very aggressive in the last few months, even biting my hand when I'm cleaning the tank.By the way he told me that clowns will breed constantly if food is available, also they would breed in a dirty puddle if you let them, raising the fry is the hard part.
Good luck.