I finally got the last of my fish into a QT and so far the only thing I have lost is my favorite fish, my flame angel. I am treating with copper and the tangs seem to be the first coming back. Now my question is about the display tank. I know i need to quarantine for about a month and was wondering if leaving the main tank "fallow" means that the snails and crabs also need to come out? I have read that the snails and crabs cannot be hosts to the parasite but can transport the parasite by the water in their shells. To me this means I can leave them there, they would die quickly in QT, and in a month or so the tank should be parasite free.