Add 2 females to every male plant the tank well, have some moss or other fine leaf plants growing in your tank and have floating plants that have long fluffy roots that hang in the water (I use water hyacinths) and let them mature and nature take it's course. My threadfins spawn off and on in both the fissens (a type of moss) and the roots of the hyacinths. Forktails do the same but if you want to actually try to get fry you wil need to remove the adults or predation will likely occur. They also usually spawn in the mornings. My Threadfins spawn first thing in the morning right after eating.