Gouramis need tropical conditions so aren't good tank mates for goldfish. However, they can be kept in a community tank with other peaceful community species.
I too have a new azalea root in my tank. it's probably been in for about a week and it also has this coating of fuzz. I think it is just a harmless bio film and has had no affect on my fish, however ri am not completely sure. It hasn't turned my water cloudy or anything like that. My tank is...