the sizes were fine. you need a group of fish as apposed to a pair (that will cut down on aggression). give them plenty of rock work and a large tank. they will breed on their own just fine
males are supposed to bigger than the females or the females will ignore them. im going to strip one of my female auratus of her fry on the weekend. only 1 or 2 ever survive in the main tank. its her 3rd spawn in about 6 months