Had 3.
Powder Blue,
Regular (which I call 'tiger striped')
and Flame Red
all together, living in a 12 gallon just fine for 1 year.
I noticed the more red they had, the more aggression. So the peking order went Flame- Tiger - Powder.
They also like some live plants.
Then I Moved them all into a 29 gallon and introduced a Leopard Ctenopoma to the tank. As they Leopard was small, they all got along fine. Once the Leopard became larger then the dwarfs, he became more aggressive toward them.
One died from being picked on. The next died a month or two later... not from direct results, nipped fins and such, but just the stress from constantly being harrassed. The third (flame) did ok for a lot longer, until he got sick from an unquarantined addition, which obviosly goes to show that even though he was surviving fine, he was still under duress.
The last one died almost 2 years after I got them.
Great fish, colorful. Most get along ok (do your research though, not all). I would still have them in my tank if they weren't related to the Leopard, and could get along ok.