But in fact more than one fish has been called green terror, it partly depends which country and their history with the fish, or who you've been listening to, so "green terror" can be any of a few Andinoacra. As an informal name in the first place, what matters is their scientific name. Here's the longer answer, from one of my posts in another thread:
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 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 neither the white edged or 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 he's not a biologist. Wayne Leibel who wrote the article above is a biologist, as is Sven Kullander and his colleagues who separated stalsbergi from rivulatus. That debate, which is the true rivulatus, is over. Alf was mistaken, as were others who insisted back in the day that the Peru fish was rivulatus.
Some of the stalsbergi as 'true' green terror theory comes from Alf, also hobbyists who don't know the history and repeat what they've heard from other hobbyists who don't know the history, besides 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... but there it is, the German article calling what we now know to be 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 call them green terrors in the first place. What you believe depends on who you listen to or what you want to believe.