Oh, I don't doubt it. I've known a lot of old hippies who were pretty ingenious when it came to creating systems that were fairly self sufficient. As you say though, the maintenance lies elsewhere, just not in water changes. As it was explained to me, we don't keep fish, we keep water.Hello Pes...
That's right, No water changes, ever. I just top off the tanks every couple of days with distilled water. The tanks are open, no cover. This is to allow the house plant to grow above the tank. The roots of the plant remove all forms of nitrogen from the dissolving fish waste material and I feed the fish a diet that replaces the minerals in the water. That's it.
Do you think it's possible to extend such a setup to a 3 gallon Betta tank? Curious because I own a tank that was ostensibly designed for such. Made by Top Fin.