Have you got a boy & girl borelli? Females are yellowish and have short rounded fins. Males get bigger and have more colour and long pointed fins.
Feed them 3 times a day on frozen prawn & fish, or live food like mozzie larvae and daphnia.
Do daily partial water changes for a couple of weeks and if that doesn't help stop doing them for a week, then do a 50% water change.
Keep the temperature around 26-28C
Have lots of plants in the tank and maybe add some small peaceful fish to act as dither fish. They don't normally need dither fish but if they are shy and hide a lot. Then a small group of peaceful tetras or rasboras can help encourage them to spend more time out and about.
If the fish are comfortable and well fed they will breed.