hmmm...in my opinion, i would ideally just keep 1 in a 2.5 gallon tank just b/c it gives each better enough space to swim...and about a male and female together I'm not sure if it would be ideal for the female b/c she might produce a lot eggs and then be uncomfortable since you wont be breeding her..Please anyone, correct me if I'm wrong..Best of Luck though!
I have a 2.5 gallon divided with a male on one side and a female on the other.. My little female Yessica(a.k.a Stressica since she is almost always stressed) is fine in the tank she loves to watch Roger do stuff. She hasent been stressed since I moved her in there. But it probably depends on the betta.
I could make you one but I probably wouldnt be able to get it to where you are. I just made it out of plastic canvas. I cut it out and put it in. Plain and simple.