Yes and no. They are more aggressive so they harass each other. But they are also more susceptible to illness due to physical features (long gut) and therefore quick to become ill when harassed. IME Demasoni are the poster child for what we commonly refer to as bloat in the hobby.
They don't always do well in the presence of even more aggressive species. Survive but not thrive.
Finally since you stock such a large number you have to tear the tank down a lot. When you fill the tank to the waterline with rocks, it can take a while to remove them and replace them. You have to net the harassed fish which is a given until you have removed all but 3 males. And ongoing to net holding females (if you plan to collect fry) they look so much alike I never have luck getting the one I want unless the rocks are all out of the way.
BTW it is not impossible to keep demasoni in smaller numbers if you ensure 1m and lots of females. BC is doing this. I continue to think the large population has better odds of success. This goes back to Ad Konings who writes about an overcrowded species tank of demasoni being a favorite and others in the wholesale business who noticed that the crowded demasoni tanks fared better than the sparser ones. It also reflects my own experience.
Thanks for some insight on these beautiful little fish, I've been doing a lot of research on them and believe I'm going to try the stocking numbers you suggest, I will post a picture once I have everything done, thanks again Dj