Them breeding in hobby set up's is rarely to non reported. You'd need HEAVY surface vegetation for one. Support them with a variety of healthy foods ( live, frozen and vegetables). Also they require soft, slightly acidic water to trigger a spawn (hope you have that?).
ASAP if you ever see eggs from them within the plants, remove the plants (and eggs) to a nursery, otherwise the parents themselves and/ or your other fish will eat them quickly.
And no, it's kinda like us humans you know...there's nothing you can really *do* to make them wanna have baby's ya see...
that's if its even a couple, which you really can't determine if it is or not.