So you don't agree with keeping tetras that often live in groups of hundreds in the wild?
If we decide to keep fish we have an obligation to recognize their expectations (in the genetic makeup of the species) and provide the best we can. We know these things matter. A study a few years ago proved without any question that shoaling fish kept in groups of 10 as opposed to groups of 1, 3 and 5, were in better health, had significantly less aggressive tendencies, digested their food better, etc, etc. One of the species studied was the Tiger Barb, and the authors noted that the fish placed together in groups less than 10 became so violent toward each other so rapidly, that they took those tanks/fish out of the study to avoid inhumanity to the fish. They commented that this behaviour supported the general view in the hobby that this species must be kept in larger groups.
The point is though you will never get anywhere close to matching their wild conditions. If you did they would die a lot quicker anyway. Do you think the majority of fish care if the plants and rocks in the tank are the same as they would have in their native habitat? Or do you think maybe all they care about is that they have the right amount of cover, or substrate, or whatever to be close enough for them to go through their normal behavior?
It depends what you mean by "natural conditions." The items I mentioned previously will not shorten their lives, they will allow them to live to and maybe sometimes beyond. The whole point is avoiding stress, so why would one introduce severe stress to replicate the habitat predators? That makes no sense at all. And yes, having the cover, substrate, etc they "expect" because it is inherent to the species is what matters, and what the fish do care about. We all know what placing a fish in a bare tank does. This is all part of the same underlying issue.
Also I really hope this isn't coming across as becoming personal. I'm really enjoy debating this kind of thing and it is something that should be argued from all sides for the sake of the welfare of the animals we keep and the improvement of the hobby.
I certainly agree, thank you.