Eventually the male will convince an eggy female to go into the cave, and spawn. They don't act like pairs in the sense that cichlids or other fish do, if the male is hiding in the cave fanning you probably have eggs.
Yes!.... They are in a tank outside, but no..... I've never seen this before.... the tank is full of mosquito larvae swimming around with the fish...... Don't they eat any live foods??? or are there just so many that they've had their fill???....
It worries me though that the (big) male has selected the smallest container to take his day refuge in.... I cannot imagine that he'll want to breed in this??.. He virtually has to reverse out the dome to get out....
As it is with many other fish.... will a water change also induce spawning activity??