The secret to getting them to spawn for me is as follows:
1. Healthy, well fed fish. As with all small sp. of fish, fresh hatch BBS. I alternate feedings with the shrimp and Hikari micro-pellets.
2. Small, separate well aged aquarium with plenty of java moss, or any other bushy plant. Believe it or not, the males will use this as their retreat as the females become quite aggressive towards the males advances. The eggs are not laid in the plants, they are scattered all over the BARE BOTTOM of the tank.
3. Introduce one male and one or more heavily gravid females.
4. Conduct a partial water change of NO MORE than 25%.
5. Have aged, dechlorinated and REFRIGERATED water ready. As most of us know, WCMM like cooler water, e.g. 65-70 degrees. The cool water is what you will use to replace the 25% you siphoned off. Make shure you allow the cool water to warm up to around 45-50 degrees before pouring into the aquarium. This introduction of cool water induces them to spawn. Remove the breeders after two days and the eggs should hatch in about a week or less. Have micro-worms and BBS ready.