Joseph, did you put the two remaining fish in a smaller tank so it is easier to do 100% daily water changes? If your fish are hiding it is likely because they are scared. Discus are schooling fish so in a group of 2 they probably feel vulnerable and will hide behind things. Either that or they are just still reacting to the ammonia poisoning left over from the last tank. What are you doing to cycle the bigger tank in the meantime. I saw someone suggested seachem stability, this product is a bandaid and will not cycle your tank. You need to get some ammonia, and add ammonia every day until you see zero nitrites, zero ammonia, and a visible nitrate reading. That is the only way you know you have cycled your tank. When the nitrogen cycle is completed, the beneficial bacteria can turn ammonia into nitrate so you will have a nitrate reading. this will take several weeks to accomplish.