seeking thoughts on pair of orange spotted blue file fish new aggression

[Fish Think Pink]

I am seeking thoughts on my pair of orange spotted blue file fish that used to get along for this past year. They've just started aggressively chasing one another. Both are female (solid black flap). They've doubled in length and tripled in width in the past year since I bought them from another hobbyist on this site (love our Marketplace). Everything I read seems to indicate they do well in groups... is it 2 that is just not enough to spread aggression? Is it because they've reached over 2 inches in length so now they behave differently?

I really just want them to go back to the sweet personalities they've had until very recently... Pictures are lousy as I just finished stirring up sand during water change



You can not tell below, but under the return is the other file fish... being stalked by the file fish you can sort of see in my photo:

 

[IowaKGB]

I don’t know much about this species. However, do you think that maybe they have reached sexual maturity and maybe they are both males and fighting due to that? I know sometimes other fish that I’ve kept have gotten a little grumpier as they got older and out of that juvenile stage.

 

[Fish Think Pink]

Both have solid black underside fin, lacking spots which would indicate male so this is why I think both are female. Yes, I am concerned about coming out of juvenile stage which would indicate this will be an ongoing problem.

What confuses me about the chasing is almost every post I read about the species talks about having groups... I am torn between getting more (but where...?!) to dissipate the aggression (thinking of anthias), or dividing them up (which likely means dividing for life and I love(d) having them swim together (until now, when its maniacal chasing))