Some of my favorite species to keep, have been rheophillic cichlid species of Central America. My problem has always been getting enough flow, to hold aggression down, even with pumps of over 2000 GPH aimed into a tank.
Here are some photos of a stream in Panama, that might be an example.
Usually the only aquatic plants are algae, although plenty of overhanging terrestrial vegetation.
But even the slower flowing rivers I visited, (although serious flow compared to most aquariums), were generally poorly forested below the surface.
Some shots of a tributary of the Rio Magdalena river in Colombia.
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