This sounds interesting! I'm guessing it must be planted? I've heard a lot about heavily planted tanks and how this can be a natural filtration system.

Good morning...

The tank uses a house plant called a Chinese evergreen or "Aglaonema". You rinse off all the potting soil and immerse the root system in the tank water with the leaves above. The tank is open, so there's some water lost to evaporation. You top off this lost water with either Distilled or water from a Reverse Osmosis system, so no minerals are added to the water. The plant roots remove all three forms of nitrogen from the dissolving fish waste and the water chemistry stays balanced. I have one that's been running for some time and can provide photos and instructions for set up. Just another interesting and fun means of tank keeping that requires little maintenance.

Have a restful holiday!

CK

Hello dusky...

I have Fancy Guppies in my 20 gallon tank. You could change the tank size to fit any sized fish. You'd just need to add more plants. I keep Comets and the standard type Goldfish too. But, they're in a larger tank and I do weekly, large water changes. This tank doesn't have the immersed plants. If you do keep large tanks using the house plants as the natural filter, you'd likely need an RO system at home. There would be a considerable amount of water that's lost to evaporation and replacing it with RO or Distilled water would be expensive.

CK

Hello 1...

The system is simple. You need only to remove the ammonia from the water before there's time for it affect the health of the fish. The root system of the house plant does this, so there's no nitrite or nitrate in the water. The other requirement is, you must maintain healthy levels of all the trace minerals. These are generally lost to constant filtration and use by the fish, plants and the bacteria colony that lives on the surfaces inside the tank. You do this by feeding the fish and plants foods that contain the minerals. I top off my "no water change" tanks with distilled water. RO water can be a little acidic and I want the pH to be neutral or higher. Fish, in general, prefer more basic water. Besides keeping the plants trimmed of any dead leaves, topping off the tank and servicing the filtration system, there's really no other maintenance required.

CK