Female bettas aren’t as territorial as males and are able to coexist together, don’t fret. I’m guessing from the pic that you have an Eclipse 12 or bigger system. The rule is 1 gallon per fish inch, you should be fine as long as you do weekly water changes. The male betta will be fine in the pond though he’s more susceptible to outside elements. i.e. Bird might go fishing.

Sorry for the long post, but I thought some of the previous posters might’ve freaked you out.

The main thing is to keep it clean, the smaller the tank, the more important it is to do partial water changes regularly. I can’t tell you how many fish tanks we had when I was a kid, salt water, fresh water, plus I worked at a pet shop for awhile. I’m staring right now at a 72 gal. tank we don’t know what to do with! Might be fun to set it up with oodles of little neons darting about. I just don’t want a bunch of big fish again though. Big fish = big poopies.