Originally Posted by
danotaylor
When I introduced a hero Asian discus to a group of healthy discus spawned by our site owner Al, I had 1 dead and many struggling discus within 48hours. In retrospect I noticed a few struggling within 24 hours of introducing the hero fish. The Asian discus was clearly an immune carrier of something the US domestics were not immune too, though all my asian discus were happy and healthy in their own tank for over 9 months. Brian (Jeep) advised me on a strong salt treatment, 1tbsp per gallon, which freaked me out as it equated to just over 2 lbs of salt. This treatment cured the problem completely. I then treated the Asian discus tank with the same strength salt treatment and was then able to successfully introduced the US bred domestic strain to the Asian discus tank without any further problems.
I guess what I was trying to say is that in my experience the cross contamination was extremely quick and deadly. Good old salt worked a treat!