My approach would be to float the bags in the quarantine tank to allow the temperatures of the bag water and quarantine water to equalize, open the bag and immediately put them directly into the quarantine tank, disposing of the transport water due to high ammonia levels in the transport water. Allow the fish to stay in the quarantine for 4 to 6 weeks to be sure that there is little or no chance of KHV and if there is no flashing, breaching, thickened slime coat or other signs of distress, I would not treat. For the pond, I would go ahead and treat it to eliminate the stressors that are causing the flashing or other signs of distress before the new fish go into the pond. As for the treatment of the pond, I have used PP and actually prefer it, but many like the formalin malachite green formulation better. With the PP, I like to have available a means of measuring the concentration (https://sensafe.com/sensafe-permanganate/ which are available in US and EU, or chlorine test strips {3ppm chlorine = 2ppm PP}) and keep adding the PP as the measured concentration falls during treatment. This allows for one treatment of 5 or 6 hours without having to come back on subsequent days and retreat. Formalin and PP are both expended consuming organics, and with Formalin, there is no test for concentration for continuous maintenance during the treatment. With the FMG solution, the treatment starts with a 25% water change before each of the three doses, where large changes remove organics and free swimmers, making the treatment more effective.
Zone 7 A/B
Keep your words sweet. You never know when you may have to eat them.
Richard