In my area, male longears get to about 6" tops, usually a bit under. However, I've never seen a female longear that big. In areas primarily populated by longears, all of the longears tend to fall under one of four categories. Those are:
Big buff colorful males (usually in nests)
Smaller but still colorful males that slink around hoping to find good spots
Tiny babies lurking in the plants
And small, dull longears that often have vertical stripes. These last ones seem to be the females. They don't engage in territorial spats, for one thing. Also, I've seen longears in this category actively engaged in spawning with a male. They're often something like half the size of the male they're breeding with, rarely that much larger. I think the biggest I've seen is a four-incher.
Do female longears normally stay smaller than males? I ask because there's one in my sunny tank that I'm pretty certain is a female, and it's a little thing that usually hides to avoid being bullied. I'm thinking of transferring it to my new pond, but I don't want it to terrorize/eat my shiners, darters, and gambusia. A little 3 1/2" sunny probably wouldn't do any of that.