Buy a pair of flowerhorns, or seperate ones. Make sure they are male and female. Then place the female in the breeding tank and the male in a seperate tank. Condition them for 3 weeks with 3-4 small feedings per day. This may consist on Earthworms, Brine Shrimp, Bloodworms, Pellets and Flakes. During the 3 weeks, you have pretty much juiced up the fish and they should be looking better with brighter colours. The female particualy. She should be full of eggs.
Now introduce the male into the tank and add a 2-3" convict as a dither. They should spawn within 2 weeks. But if the male or female gets too aggressive, use a dividder to seperate them.