I had four males in a small 6g hex. They were fine for a while, but when one died all hell broke loose, lots of nipping and fighting... Now I am shuffling them around between two tanks until their new one is cycled.
Having said that, I think it would work as long as the tank was big enough and as long as you had an odd number, 7+. Three is the worst - they form into a 2 and a 1 and the 1 gets picked on, this is fairly common behaviour apparently. And I would definitely fill the tank with plants and include some hiding places so that they aren't always in each others' faces.