I must have been pretty lucky with my pair. I got the male (around 5 inches) and then found the female about a month later (3.5 inches). Bruiser chased her around HIS tank for about an hour, but now they're always with eachother. She has her own small hiding spaces should he turn aggressive, but i've not seen any signs so far. I'd try large water changes, and when adding the water back to the tank try having it colder than the aquarium temp so that it simulates a heavy rain.
One other question would be what size the tank is. If they can't establish a territory they might not spawn.
One other question would be what size the tank is. If they can't establish a territory they might not spawn.