clownfishes keep fighting

[fishay]

I bought 2 ocellaris clowns about a month ago. Up until a few days ago, one of them would occasionally charge the other. The one being charged would do the weird twitch thing so I assumed it would be ok since it was showing submission to the aggressive clown. But now, the previously submissive one chases the other clown around the tank relentlessly. The clown being chased just swims near my frag rack now. So why the sudden change in behavior? Did I end up with 2 females or is there still a chance they will form a pair?