TNG
Fishaholic
Well, that also depends on what kind of bettas we are talking about. When we talk about bettas, most people think that it's only related to the Betta splendens while there are more betta species that live in different conditions.
I believe the OP is about B splendens.
If any members who have info on other species of bettas which live in nature exclusively with labyrinth fish (i.e. in environment which only supports labyrinth fish) please share what you know. This is the knowledge that we can appreciate.