http://www.tfhdigital.com/tfh/201005/?pg=35#pg35
To summarize-- First GT imports to the US were from Ecuador in the 1970s, in other words
rivulatus. They were very expensive, especially the orange edged variation. Keepers called them terrors because these adult wild male rivulatus were so aggressive. Meanwhile, the original and meaningful debate was not over the hobbyist nickname 'green terror' but over the science: which fish is rivulatus. Some had the Peru fish, what's now stalsbergi, as the true
rivulatus. At one point, a German article called what is now stalsbergi 'the green terror that isn't'. It was not the white edged Ecuador and not the gold edged Ecuador fish, it was a third fish.
I myself had cichlid books back in the day with photos of stalsbergi stating they were the true
rivulatus. This turned out wrong, the Eduador fish is rivulatus, and the Peru fish is now stalsbergi. Alf Stalsberg insisted for years stalsbergi was the true rivulatus but had to acquiesce when biologists officially determined the Ecuador fish is rivulatus, not the Peru fish (stalsbergi). Alf is knowledgeable, he has his opinions, but last time I checked he's not a biologist. Wayne Leibel who wrote the article above is a biologist, as is Sven Kullander and biologist colleagues separated stalsbergi from rivulatus. That debate, which is the true rivulatus, is over. Alf was wrong, as were others who insisted back in the day that the Peru fish was rivulatus.
Some of the stalsbergi as 'true' green terror meme comes from Alf, also hobbyists who don't know the history who repeat what they've heard from other hobbyists who don't know the history, and years of confusion over which was the true
rivulatus. I've seen the claim that the first fish imported to Germany was stalsbergi and therefore it's the original GT, or at least it's the German GT... yet there's the German article about stalsbergi 'the green terror that isn't'.
Alf still has a page up that insists rivulatus is not really a green terror. Whatever.
True GT,
false GT, it's window dressing, a hobbyist debate over a manufactured mystique, much ado about nothing. In some countries they don't even call them green terrors in the first place. What you believe depends on who you listen to or what you want to believe.