@Colin_T. This story dates back a few years, but here goes.
I wanted a new challenge so decided to breed African Butterflies. I bought eight fish from an importer sight unseen. Of those eight fish there were two males the rest females, I kept the best three females and the males. Raised them up in the tank under the Discus, with the whiptails. Then purpose built a four-foot tank for them that was just twelve inches deep. I ran them in that alone with about six inches of water, as the days lengthened,and the early morning sun started to hit the tank, I slowly raised the water to about ten inches. The tank had a peat base pH of 6.2-6.5, I don't know the hardness. They were fed exclusively on Mosquito larvae and adults. The tank was always full of food.
Even though I never saw any eggs or young I'm fairly sure they spawned. The activity in the tank suggested that. I consider this unfinished business and will do it again sometime. I think the tank needs to be bigger most probably six feet by two feet and a foot deep. The activity of these fish was amazing to watch but they looked like they ran out of space.