Never had barbs before because I know they can get a lil nippy and I always had peaceful community tanks.
But I had to restock and wanted a little more life, and stuff to watch in the tank. I like the pecking order, and they are sure fun to feed.
I'm gonna leave the neons and harlenquins in as dither fish unless I notice any nibbling. And yea, 6 sounds like a good number and I will keep adding, until the traffic is sufficient for my eyes, and of course the ammonia and nitrate levels test well. The tank is heavily filtered (2 eheim 2217s and a large biowheel HOB for surface flow)