Dwarf puffer

all puffers temperments vary between individuals, it not possible to say something will work 100% of the time. for a 10 gallon I would say 2-3 would be best but 1M and 3 F COULD work if the tank was well planted and all were added together.

I presently have 2 males & 4 females in a 25 gal hex. The back of the tank is ringed with various fake plants and there are 4 seperate caves in the front. The only one thet seems to be territorial is one of the males(named Kinky) who claimed one of the caves as his own and will defend it against all commers. The females will chase each other, and will gang up on Kinky if he gets out of line, but they haven't done each other any damage yet. I will have to wait until they mature a little more to see if this will be a permanent arrangement.
IMHO as long as you have plenty of cover and try to reduce their direct sight lines through the tank (hills and valleys in the substrata make a difference to these guys) they should get along Ok.

Oh by the way my 6 pack have been together pretty much from the begining, I got 3 one day, and bought 3 more the next day. They have been together ever since (including a 2 week stint in a 1 Gal tank until their new tank was ready) , being as how they grew up together they may have had the pecking order settled when they were still very young.