Regardless of how we have quarantined our discus we highly recommend that all our customers quarantine any new fish. Why you ask if we have already done this.? Even if you get your discus from the same supplier there is always a change you may run in to problems if you introduce your new discus directly into your aquarium. Most people who have a discus setup will have other types of fish in their tank. Such as Tetras, corrys, bristle nose cat fish etc etc. There may be a chance that your newly prized discus may not be immune to some pathogens introduced into your tank.
Not everyone will have separate facilities (Fish House) to quarantine their fish; however we would highly recommend the following:
Have at least one quarantine tank available for your new arrivals.
Have separate nets and other equipment for the quarantine tank.
If possible keep the quarantine as far away from your main tank.
Once you have purchased your new discus place it in the quarantine tank. After 1 - 2 weeks introduce your sacrificial lamb. You will usually see any problems after 2-4 days. After a further 2-3 weeks you should be able to safely mix your discus. If you have any issue please contact us immediately (or your supplier).
The worst cases scenario is that you have issues with your new fish (or sacrificial lamb) and not your whole display tank.
Follow these simple procedures and you will generally have a healthy aquarium full of Discus. Although not always guaranteed, but you have given your Discus the best possible chance.