Diana Walstad Influenced Experimental Tank

This is how my NPT (natural planted tank) looks like today. A lot of plants die in my experiment - it's done purposely to find out what can survive and what cannot survive. The survival rate of the fishes in this tank is surprisingly high, despite no filter is used. In fact the Kribs bred, so were the Platies and Endlers. There's always almost no survival for the livebearers' fry because they got eaten up. It's a different story for Kribs as the parents protected the young ones (I lost the mother Kribs which jumped out of the tank not too long ago). The water is always a bit murky because my fishes mess up the tank all the time including digging. Yeah, I know the tank is overloaded with too many fishes.

I do weekly water changes. I don't follow Diana Walstad's methods very strictly. I could not stop myself from changing the water because the water is very murky and the bottom of the tank is very dirty too as you can see from the photo. Please note that the photo was taken after I changed the water. It could be worse before changing the water. I lost a few fishes in the past when I skipped changing water for 2 weeks in a row. So I've decided not to skip changing water from then onwards. The situation may improve if I have a filter but I've decided not to have one because I have consumed too much electricity in this hobby.

Plants:
Only Sagittaria Subulata, an unknown plant, duckweeds, bits and pieces of Blyxa (I think they're dying off) and water wisteria (newly re-introduced. The old batch died) are in the tank. I have killed many plants in this tank i.e. narrow leaf ferns, marsilea, various species of rotala, hornwort, bacopa, ...and the list goes on.