Just wondering, could 2 female bettas be kept in a desktop aquarium? Such as a 3 or five gallon tank? I'm not sure if they need large aquariums to live together peacefully, or if they can get by in a relatively small hex aquarium.
the smallest recommended set up is 10 gal with 4-6 females. this allows them to establish a pecking order without any one girl getting too picked on/beat up!
I think that you'll need a 10g. If you kept less in a smaller tank, for example: 3 females in a 5g, the weakest one would be picked on incessantly by the stronger ones. If you have six of them, you'll have no bickering problems, but in order to house that many, you'll need some space (at least 10g).
2 females will most likely kill each other - or at least one of them would end up pretty wounded. They usually have to establish who will be the authority of the tank, and be the general resident hag - and when one of them decides to be that one, the other one will be tormented mercilessly.
You could probably do 4, 5 or 6 in a 10G tank, no more or less.
Awe, bummer--Actually, I mostly like the idea of having multiple fish in a filterless bowl (a large one though) Are there any breeds that are air-gulping that can live peacefully together?