I must note there is no big disagreement between Wednesday's thoughts and mine.
The long and narrow tanks are not catfish friendly or, maybe, not very friendly to any (most) fish unless they truly don't swim much, like Cephalosilurus spp for instance.
A better tank for a fish, not viewer, would have its length be 2x the width... but the long and skinny tanks make fish sit and move preferentially sidewise to the viewer, thus, maximizing the best viewing angle of the animal.
I imagine an ideal tank shape (again, mostly for the fish, not the viewer) would have a circular footprint:
-- no corners to hit for a fish,
-- no need to turn around every 2-4 tail flaps,
-- minimization of bruised snouts,
-- long-barbelled Pims would not always be able to touch front and back glass simultaneously and hence feel trapped = stressed,
-- smooth current, no dead spots, better aeration, less detritus accumulation, etc.
But curvature distorts the view and can be unpleasant to look at, even cause an eye strain, headache. The greater the curvature, the stronger the effect.
A cynic would say it's another one of those "wonderful" damned if you do, damned if you don't occasions
but understanding these things and monkeying with them makes our hobby edifying and interesting, IMHO.