Hi Kara
That tank size, while fine for one betta, is not suitable for more than one fish. Female bettas, like their male counterparts, are very agressive, and would kill other fish in such a confined space.
Furthermore, female bettas should never be housed together in anything less than 10 gallons and any number fewer than five. People might post their rare exception to this rule, but I ask that you ignore them; the point of this forum is to provide advice based on what is typical for the species, and it is general knowledge that female bettas, as a rule, do not get along well in anything but the aforementioned conditions (and even at that, it is not guarenteed if your girl is agressive).
Your little lady is probably very happy alone in her tank without the stress of other fish, and likely enjoys her swimming space. I say pamper and enjoy her.
edit: also, is little bit young? She looks very young in the picture; she'll get a good deal bigger, just so you know, though not so large as a male. I'm sure once she's full grown it won't seem like a waste of tank space to have her in there
It'll be pretty boring with just her in a 2 gallon, she is so tiny.
