Young dwarf puffer problem

I purchased seven very young dwarf puffers recently and placed them all into a ten gallon planted tank until they can be sexed and broken into safe, small groups (IE one male and a few females). Since DPs are usually young when they become available for sale, and usually can't be sexed yet, I thought buying a small group would be OK and that they would get along until they matured. However, they are starting to fight some, and I am not sure if this will lead to fatalities or if it is no big deal. One of them puffed a little today from fighting which worried me.

They are 1/3 to 1/2 inch and the males have no black lines on the abdomen yet. They are eating well and seem healthy.

Can anyone advise me as to whether it is too unsafe to keep them in a group until I can sex them?

I constantly see these unsexable baby DPs in stores and I am wondering what people to about arranging sexed pairings or groups - don't people have to buy them unsexed in small groups? Do they end up killing each other even as juveniles? When does the fatal aggression kick in?

Thank you for any information about this.

Lainey