They are small fish, about 1.5" full grown (if your talking about the scarlet badis. They have a HUGE personality packed into a tiny body lol. They are quite hardy given you keep water quality high. The drawback about them is that they rarely eat any prepared foods. They are very deliberate eaters too, so fast fish that would steal their food is not a good choice with them. I have managed to get them to eat Frozen foods such as Cyclops, frozen blood worms, frozen tubiflex worms. Females are rarely found for sale, and males can get a bit territorial. They also stick around the bottom of the tank. Great little fish.
An apisto would not do well in a tank that small, they need more space, but you could fit a few male scarlet badis in there.
There are other species of badis, they are much larger, and in my opinion not as colorful as the scarlet.
http://www.seriouslyfish.com/profile.php?genus=Dario&species=dario&id=41
I think there is some relation to CICHLIDS/ ANABANTOIDS somewhere lol