I offen thought about this for 8 male bettas in a 10gal. The reason being was I wanted to house many young male bettas in one tank before selling them. Housing them seperately cost alot in heaters and wouldn't be worth it. Sorry I lost the diagram I made. The dividers would be made of green cloth mesh for water to flow through. Green so the male bettas couldn't see eachother through the mesh and flare at eachother at the time, which would stress them out. Since the tempature wouldn't be as affective with mesh in the way you would have to buy to heaters and put them on very low in opopsite corners on either side of the tank. Put the thermometer in the middle bettas ''room'' The power filter would be used but is the most challenging. You would have to have a seperate intake for each betta room you have and each one needs to go to the main filter.You have to buy extra plastic pipes to attach to the main intake pipe in the filter. You would have to use silicone to attach the intakes together. Besides this the intakes most go through the mesh so you would cut hole for the intakes to get in and then silicone them to the intake so the fish can't get through the hole. I never actually used the idea because I changed my mind about breed bettas. I don't have enough time or for something that complex.