Usually, if you want fish to hit it off, separate fish first. Normally this builds up to a lonely fish that will appreciate some company after a while. Condition them for breeding by feeding well with good live foods, then put them together, they should start showing interest in each other fairly soon. This is how I get my pencilfish to get it on recently. In the main tank, the male just flair at the females but don't do anything bout it, but once in the breeding tank together, they spawned on the first night.