Before we jump to any conclusions, understand that discus are timid fish, and due to the capturing/transporting process, the undergo severe stress. They may just need to recover, which could take a couple of weeks. Make sure they have a place to hide. If you don't have any plants, you may want to go out and pick up some fake floating plants at least. When discus are stressed, they will do anything to hide from the light, including hiding in each other's shadows. Also they max water pH should be about 7.6, and the max hardness should be about 15 degrees. Don't forget that the temp should be at least 82F, up to 88F or 90F. Make certain this is correct. If your other fish don't like it, either get rid of them, or the discus.
However, if they did not look like this when you got them, there may be a problem. I won't even consider disease until we have the basics ironed out. You will do more harm than good by treating for disease when all you may need to do is adjust the water temp.