Hi Nefertia.
(...Oh oh...here he goes again...
)
I have a pack of 6 Indian Dwarf Puffers (Tetraodon travancoricus) and so far the only tankmate I've discovered that they will live peacefully with are my 4 Bumblebee Gobies, unfortunately I will have to move the BBG's to a brackish water tank soon, leaving the Puffers alone in their 25 Gal Hex tank.
You may want to try Peacock Gudgeons (FW Gobies). From what I've been able to find on out they are similar to the BBG's in temperment, so they should make good roomies for the Dwarfs (my little pack will gang up on any aggressive fish that tries to harrass one of them, and give him a right good thumpin')
I also have 3 Golden Ramshorn snails in the tank as a cleanup crew. The puffers like to try and eat them, but the snails are just too large for them. The snails usually suffer a few nips, and rarely get any peace, but they seem to have a system worked out. Each day there will be a different snail out front being stalked by a couple of the puffers, while the other 2 are busy cleaning up the tank. ( in the lfs around here the "Mystery snails" seem to be a mix of ramshorns & smaller apple snails)
IMO you could house 1 male & 3 females comfortably in your 10 gal, just make sure you have lots of plants/caves/logs etc for them to sleep in, mine seem to choose 2 or 3 different sleeping spots to call their own (see what happens when someone asks about Dwarf puffers...I cant shut up...Luv my babies
), and break up the lines of sight (the puffers sight not yours) as much as possible to cut down on the chasing a bit.
In my tank I placed plants in a semi circle around the back and sides and put 4 caves (I used shot glasses for caves and covered them with sand) in the open space at the front. I also contoured the sand in the open space so that there are hills and valleys, this seems to have cut down on the chasing and nipping quite a bit.
I also removed some of the plant parts from their base and let them float freely on the surface, the pack loves to play hide and seek in the floaters and will ride the plants as they spiral through the current from my filter.....looks like great fun.
HTH
Don.