Nice looking pair.
In my experince with spawning these when they go into spawning mode i do large 80% water changes(twice several days apart)you dont really need to cool the water to much,the new water will trigger them fine,and the larger water changes will get the female ready sooner and she will lay larger spawns,also freeze dried earthworms and krill will condition them to have large spawns(feed when they go into spawning mode)you will be surprised the size of spawns they can have.