I suppose it would be better to define what I meant by risk, by this I mean risk that parasites enter the display tank. To me this is why I quarantine, its far less about protecting the fish in QT than it is about insuring the health of the display stock, hence the debate about aerosol transfer. Surely with tank transfer there is always a risk that parasites enter the display since the water they have been in has not been treated to kill off said parasites. I don't see logically how this could ever be considered less risky than a fish that's been exposed to water that has been prophylactically treated to kill pathogens. I get how the TT method works and can be very effective , I just don't get the rhetoric that it's lower risk than the pro-active treatment of QT water.