discus pairs not producing as much or not at all after sickness?

[inkfam]

I have a couple of pairs of discus that produced fry all the time. I believe they came down with something bacterial which was quickly cured with water changes and medication. 3 months later.... not very much breeding going on and when they do eggs are turning white sometimes not sticking to cone.. Water chemistry is the same, discus are young. Has anyone experienced this? Will they ever be normal breeders again?