There is no such thing as an "Amazon" biotope. The Amazon basin and it's river systems is one of the largest on the planet. The diversity of the water bodies within that catchment is as large as the number of species present suggests.
Thus, you can have tetras from one part of "the Amazon" that live 1000km's from others and exist in totally different conditions, same is true of Corys and the rest. There may be some species that occur throughout the drainage, if so, I am unaware of them.
The same is true of plants. There are inumerable Echinodorous species, but you do not find all of them in the same place, even a large number. They are as distributed as the fauna.
Consider, at Manaus, the 2 largest tributaries of the Amazon join. The water from the Rio Solimoes and the Rio Negro are so different, they don't readily mix. They flow side by side in the same channel for kilometers, the black R. N. water to the north bank, the milky coffee of the R. S. to the south, the meeting in the middle, "the wedding of the waters" is easily visible.
Punchline is, that pretty much any tropical S. American plant from Brazil is almost certainly represented in the Amazon system somewhere.