As far as other native fish around them, you must remember that the bettas you buy in the stores and through the breeders have never been in with any other fish not even any other males or females of their own kind. they live in a jar or container by themselves totally solitary confinement. This is why they do not know how to play nice with other fish sometimes and it is a crap shoot whether or not you will get a fish that will accept other fish with it or not. they do not know that others are allowed to share their water. As soon as the fish is determined to be male it is put in its own container and remains alone until it comes to its owner (you) and the first time it sees any other fish with it will be if you put them in the tank with it since it was a tiny fry. This is a total shock to these fish.

So I would guess that no, there are no other fish that are native to its environment.

Rose