IMO it's important that both show breeding mode signs before you float a female in a male's tank. In breeding mode, the male (actually both) will swim all over the tank. SO if an aggressive female is placed with him, she will think he is running away and she will chase and attack him. Often the male will fight back and put the female in her place but the male will have torn fins by then.
If both are in breeding mode, they will play follow the leader. Either may lead the courtship process. Usually only the male would bite. But sometimes if the male isn't ready while she is, she may attack the male. Or if the male doesn't show aggressiveness (not vicious) she may also attack.
Your picture is definitely a female. She has small dorsal, ventral and anal. If you want to breed her, isolate her. After a day or two, show her a male. If she is circling around the tank, you can breed her. But if she seems to be trying to break through the glass, she's not ready.
Btw, I don't rely on bubble nest nor breeding stripes to determine my breeders. I rely on their general behavior.