It was directed at him. As I said a bit frustrated and it was referring to another post where he broke down what I said into like 5 different quotes correcting each thing. And my point wasn't that it diluted the water at all in nature. It was actually the opposite. It collects all types of bad stuff from animal waist to rotting material. None of that is present in a clean water change. That was my point is there are no truly clean water changes in nature. Aside from a natural spring or something like that.
Ok, lets accept that there are no truly clean water changes in nature, but you must accept that there are water changes which this guy says he doesn't do.
But then keeping fish in a tank isn't how they are in nature so as fishkeepers, we already accept that and have then maintain the fish as best we can.
His main tank described at the beginning has a "huge fish load" but no filtration. He doesn't have a ton of plants for the fish load so I'd be concerned about the build up of ammonia, nitrates and nitrites without daily water changes which he says he doesn't do.
Again, the only way i'd be happy with this setup would be for him to confirm his water parameters to prove his fish are ok.
Also, Colin did point out that Rainbowfish and Cardinal Tetra's prefer opposite ends of the ph spectrum so long term they won't necessarily be happy.
Some fish keepers fall into the trap of assuming that because their fish look ok "now", they're ok. Put a fish that prefers a low ph of 6.5-7 in a tank with a ph of 8 won't necessarily kill it the moment it hits the water but it could end up shortening its life somewhat as its not happy long term, so saying your fish are ok just because they're swimming around eating doesn't mean they actually are.
If we take your video, the guy claims the tank has been set up for 3-4/2-3 years but in particular, those Rainbowfish aren't that old. I'd be surprised if they were more than a year old based on my experiences. So that makes me wonder how healthy this tank actually is.
For reference, I have a dwarf Pleco that is at least 13 years old. I realise not all fish live that long but if your tank is healthy and the balance is right, your fish will be healthy and live longer.
His main aim seems to be to "not give his money to capitalists" rather than maintain the best conditions for his fish. Look its easy to criticise but I'm only doing so from my opinion. I've had over 30 years keeping fish so think I've got a good grounding at least. He may have some valid points, I'd just like to see more evidence based arguements from him rather than, 'everything looks, feels, seems fine so it must be.'