I added my pair on 5/24. I think the smaller female, which was the more aggressive recently, is becoming a male. I noticed a couple days ago her/his colors were muted and I became concerned about possible illness. She's fat and sassier than ever though. Today I watched for a long time and noticed some more male characteristics like an increased lyre shape to her tail and mottled coloring on her tail, which one article I read referred to as "stained glass" markings although hers are black not yellow. Also the orange/yellow coloration along the dorsal aspect is pronounced. I took a couple of pictures for this post and in them her yellow is much more visible than it is to my naked eye, possibly because I took the shots with an orange filter.
Here is a link to the article.
https://reefbuilders.com/2015/07/15/bellissima-bellus-variations-hybridization-genicanthus-bellus/