Keeping Betta splendens together in the same tank is always a challenge even when keeping just females in a "sorority" tank. IMO keeping both males and females together in a tank this small is just inviting problems as those fish reach sexual maturity.
+1! I reading through the post and I was going to post this. But I see someone already has.
In a bigger tank, you MIGHT be able to keep a male and female. But only if you have a big tank and A LOT of hiding places.
Just my animals:
0.2 Cornsnakes, 0.2 Bearded Dragons, 1.0 Water Dragon, 0.2.1 Crested Geckos, 1.0 Tiger Salamander, 2.0 Anoles, 0.0.2 Red Eared Slider Turtles, 0.0.1 Map Turtle, 0.0.1 Hermit Crabs, 1.0 Hamster, 1.0 Rabbit, 0.1 Horses, 2.2 Dogs, 0.2 Cats, Chickens, Ducks, Oscar Tank, Planted Bowl, 2x 10 Gallon, 2x 0.5 Gallon, 5 Gallon, and Planted 25 Gallon Tank....Is that it?