I have been trying to set up a tank in which the plants can take up all the wastes of my fish. It seems to be working now. There has been no water change for 8 months and the fish seems doing fine. Below is a picture taken two months ago. I have read before that an awful lot of plants are required to support a reasonable fish load, but I cannot find the mention of the actual amount needed. So here is my experience which may be interesting for others who wants a more balanced aquarium. My tank is 22 liters with 16 small fish like tetras, 6 cherry shrimps and many small snails. I feed my fish once everyday. It is heavily planted inside. More importantly, I opened the cover of the filter on top of the aquarium and grow from the ceramic rings there a few long branches of pothos, which have a total length of roughly 10 meters. There is no other filter medium besides the rings and the plant roots. The whole thing is about 5 meters from the window but the pothos still get some sunlight late in the afternoon. The nitrate level is around 40 ppm and I can not lower it any further. So, it really takes a lot of plants to consume all the fish wastes even for my small tank. I am lucky to have somewhere to hang them all.
