Regarding discus breeding pairs water change. How much feeding how many times should lights be off at night in breeding rooms normally when eggs & fry are there?
You can change water 25% daily. This is the normal practice. If the pair is not spawning for some time, change 100% of water, then they will spawn.
Feed them once a day preferable live food.
Light is on 24 hours in breeding room if possible. The parents can take care and feed the babies 24 hours.
Create an ideal environment in the breeding room. (Quiet, No disturbances, not much moving activities)