Spring fed streams are in reality CO2 injected because groundwater is saturated with CO2. The clarity allows green algae and submerged plants to thrive.Some of the mountain streams here in NY have almost CO2 injection, very cold, fast flowing water. underwater they are totally green with very often 5+ types of plant growing in one square foot. The tend to be very shallow (<6"), and have no fish, shrimp or red plants though, but otherwise theye look a lot like those nature aquariums.
There are share of many crystal clear mountain streams, rift lakes in East Africa, and sink hole lakes in Florida, Mexico, Indonesia and elsewhere. Weeki Wachee is a popular tourist attraction in Florida where you can swim or ride glass bottom boats to enjoy 100 ft of clarity. The rocks are covered with green algae and grazed by fish, but unfortunately, I saw Mbuna introduced to bring interest.
The Spaniards classified the Amazon waters into white water, black water and clear water. White water is sediment loaded water in the main channels, black waters are tributaries stained with tannin, and clear waters are by name clear of tannin or sediments. Clear waters are extremely rare in the Orinoco and Amazon river systems.
Here are two videos by George Fear and Ivan Mikowi on Orinoco discussed in post #84.
https://www.monsterfishkeepers.com/forums/threads/natural-habitats-of-cichlids.670096/page-4
https://www.monsterfishkeepers.com/forums/threads/natural-habitats-of-cichlids.670096/page-3
George Fear's videos are representation of majority of the habitats: water not clear, detritus and leaf litters everywhere, and dirty looking brown algae or moss covered objects.
Ivan videos show more picture perfect habitats but he acknowledged having hard time finding the 0.5% clear waters he could video.
So I am not misleading or nick picking that many riverine habitats where most of our aquarium fish came from do not have clear water or prettier scape than our aquariums.