You can divide or separate them for awhile... fatten her up...and move him into her tank...with a few pots / caves for spawning...and they'll do their thing.
I have my pair and a couple of generations of their offspring with them. The alpha male breeds with a couple of different females. Also have some grow out Hericthys with them.
There is a fatality from aggression every now and again...
Matt
Ralph;4062209; said:
Mat do you keep other fish with yours or are they alone?
my advice would be to put them both in a larger tank. if they're not getting along now in the 20 then the odds of them getting along in the future is pretty slim, especially as they reach adulthood...unless they're already adults that is.