Disease transmission via aerosol Waterborne diseases can travel through the air infecting nearby tanks? Yeah, I didn't believe it at first either. I first heard of aerosol transmission from "billsreef," a highly respected Marine Biologist who posts on Reef Central. He had this to say: This got me thinking. From my own experience and that of others, I've experienced cases where a display tank (DT) inexplicably got ich. In each case, there was a quarantine tank (QT) in close proximity to the DT. Further research on the matter turned up this study (Roberts-Thompson et al 2006): Aerosol dispersal of the fish pathogen, Amyloodinium ocellatum The abstract of which is as follows: Conclusions: Amyloodinium's (aka Marine Velvet disease) dinospore stage is similar in nature to the "free swimming" stage of other external parasites. Cryptocaryon irritans (aka Marine Ich) has a theront stage, for example. Therefore, it is logical to conclude that these are transmissible via aerosol as well. The study found that dinospores could travel in aerosol droplets up to 3 meters (or 9.84 feet) with dynamic airflow. Well, any room with an air vent or fan running can be considered "dynamic". So in light of this, I feel it is advisable to house your QT at least 10 feet away from the DT. This also applies to any two tanks that you want to ensure no cross contamination occurs. Now the study did show that aerosol transmission was only possible up to 440 mm (about 18 inches) in a room with no airflow. However, if you decide to "chance it" I would go so far as closing off all HVAC ducts to the room, which might make room temperature unstable. It is well established that "anything wet" such as hands, equipment, feeding apparatus, etc. can cross contaminate diseases & medication from one tank to another. Now we know that aerosol droplets can do the same. I think it is also very possible for medications in the water to be transmissible via aerosol droplets. No one wants copper in their reef tank!