Get a larger male, take her out, rearrange the tank, then put in the male. Then let the male establish territory. Then about a day after he's in. Drop in the female. What size tank? If its your 10 gallon that's why.. they need space. She will defend it until she gets more space. Put the female in a tank for the 1 day. I reccomend one day so that the make fully establishes territory. It can be done in way less though.
I'M ANDREW AND I'M A FISHAHOLIC
-Andrew