Sorry Diver, but I think you may have missed my point a little. Indeed fish or plants from all over the world can and do coexist in the same tank, but only if water conditions, temperature, compatibility, etc. - can be satisfied!
Jim's point, and mine also, for I too am a perfectionist!
(sorry!), is that although this is a computer simulation of an aquarium, only fish and/or plants, (and coral in the marine), should be used that could survive and flourish, were it a real life aquarium! - Hence my point that the more exotic coloured freshwater 'tropical' plants may not survive in a 'cold-water' goldfish tank!
We mix our tropical fish from all regions simply because its pretty.
No! ..... only if nature allows us to!
............. Otherwise, dead fish, - or dead plants!
ps, - Don't get me wrong though, - if some of those reddish plants are suitable, lets have em!