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Edit: just remembered something I once heard about tall tanks. Specifically tanks deeper than they are wide or long. Something about poor oxygenation and stratification of the water and dead spots. Perhaps someone can speak to this.
This may be true of static water, but often large tanks are setup with filtration, powerheads, and aeration in order to allow good circulation and oxygenation.
I have a bigger 'problem' with the hobbyist that puts three (3) large canister filters on a 55g tank because of the notion that "there's no such thing as too much filtration"! Meanwhile his fish are swimming 90 miles an hour just to remain stationary! (okay, I exaggerate, but I think we all get the point.)
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I can't really speak to the species selection...but I will point out once again that many of the fish we have in the hobby are bred and raised in tanks and ponds with water chemistries that are nothing like their wild cousins of generations past. Again, my water is moderate (neither hard nor soft) and I have Angels, Corys, Neons, and Swordtails in my 60g display tank for 10+ years and they are all robust and healthy. My water might not be good for some wild caught fish from half way around the world, but the fish I have seem to like it! I think FRESH water and high quality food is more important than a few degrees more or less of hardness.
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This reminds me of my Mom's 5g tank when I was a boy in the 50's and 60's. A metaframe with a slate bottom, a bubble up HOB with carbon and filter floss, a 1//4" of gravel. A top with an incandescent light. She always had floating anacharis. There was always a fair amount of mulm. I don't think there was ever a water change and top offs came right from the sink (chlorinated city water) without conditioner. There were 5 fish in this tank: An Angel, Black Molly, a Red Velvet Swordtail, a Cory, and another fish I can't seem to remember (senior moments!).
The point is that back in the day when little was known/understood about the nitrogen cycle, in spite of too many fish in such a small tank, few/no water changes, low quality commercial food of the day...these were all
big, beautiful fish that lived long lives!
The moral - Sometimes I think as "experienced hobbyists" we just might overthink some things, while inexperienced hobbyists underthink some things!