Sad to say, you can't keep a male and a female together. They tear each other to bits.
In the breeding tank, just a day or two is sufficient time for a male or female (usually the male) to loose a good portion of their finnage. Thats one reason that breeding is difficult. You have to time it right to keep your fish from destroying each other.
I had one female ... wait I still have her
... in the spawning tank, and everything was going well, the female was doing all the running and hiding and the male seemed more interested in his nest... so I made the mistake of leaving the house for a few hours with them both in together.
I left with the male possesing a full and long halfmoon tail... and I came back to a male with absolutely no tail (cadual) at all. He still had his dorsal and ( for the sake of the word censor I can't use the real term) lower fin.. both untouched... but he had no tail left whatsoever. The female was swimming around with a long, thin strip of his tail in her mouth and proceeded to slurp it up like a spaghetti noodle.
Males of course can't be kept with other males... but females can be kept together in sororities, IF they have known each other from a young age. It works really well with sibling sisters if they've been together since they were fry... all the females of a spawn can stay together in a large enough tank. But adult females newly introduced will make snacks of each other.
If you want to keep more than one Betta in a large tank like that... you can if you use a good devider. I must stress the ggod part there.. because Bettas are crafty and they will find their way over, under, through a devider that isen't fitted right.
We have 2 20 gals seperated with acrylic with homemade filter contraptions, as display tanks. The tank in the living room is devided into 6 compartments, and the one in my room is just split down the middle with a small submersible filter on each side for my two favorite girls, Glitter and Shimmer.
I like keeping my fish this way as there is always another one to look at. They have their time flaring at each other and calling the other names through the devider.. and then if they get scared they have plenty of plants to hide behind.
