Your newly bought discus fish, born in a farm environment, have never known what a plant or how a plant smells like. They need your help to adjust to the new environment that you are providing. How well your discus adjust to their new environment will depend on your skills and knowledge as a hobbyist to make them as comfortable and stress free as possible.
Do not put new fish into your main aquarium straight away when you receive them. Keep them in a separate tank, allowing them to rest. You do not want other fish to disturb them when they have no strength to defend themselves. Also to safeguard your current collection of fishes against disease outbreak.
Quarantine new fishes for at least a period between four to six weeks. You can shorten the quarantine time if you buy the fishes from the same reputable source. The fishes would have been quarantined before sale and treated for any diseases that may have been present.
Steps to remember which will help your fishes to acclimatize to their new environment
1) Do not feed your fishes on the first or even the second day after receiving your fishes
2) Change a portion of the water daily
3) Feed small amount of frozen bloodworms or granulated dried food and remove all uneaten food. They may not show their best of appetite but the hobbyist need not worry. Given the time they will eat.
4) Keep them in a group, discus fish feed better and feel secure in groups
5) Transfer an existing fish into the quarantine tank with your new fish and observe for a few days. If all is well, then it is safe to transfer the fishes into your show tank.