That means she's healthy :D
And its fine to just keep her in a container. They like smaller environments. But it wouldn't hurt to put her in a fish bowl.
:D
I just got 2 sunset platties and the guy at petco said they might have babies but It's hard to tell if they are boy or girl. And I really want them to have babies so how can I tell so I don't try and breed like 2 dude fish. One is slightly bigger than the other but that might be an age thing...