I have had many dominant females.
One example.
I purchased a bag of 6 juvie Vieja bifasciata, turned out to be 5 females, and 1 male, where the females kept the male from getting enough food so he was temporarily stunted.

Once I gave him a separate tank, he quickly outgrew them all.
Another ex I had 3 male Tomocichla tube, and a friend had a slightly larger female.
He gave me his female, and she quickly killed 2 of my males mated with the other, and killed him soon after spawning.
Below, here she is with a string of wrigglers, after killing the male

One more.
I had a bag of 5 Vieja zonatus, where the female killed all but 1, mated with him least 3 times, then bumped him off.
Same thing happed with a pair of Tomocichlia asfraci, where the female killed the male, and then ate the spawn.

From my point of view, dominant females can be very common.