Maybe just for the winter, put your betta in one of these nurseries. It hangs in the tank with the wal just over the water line and allows the fish in it to share the water with the bigger tank, but fish in the tank can't get into the nursery and vie versa.
Penn Plax Aquatic Nursery
Thanks for the complements, and the criticisms. I know that purists, prefer the green tanks, but I loved the way the corals looked and preferred the ease of a freshwater tank. It's a just a matter of taste I guess.
All the fish that are in there actually work pretty well together. They're...