Depends on collection point.
Alf stalsberg has collection data from many collection points for a rivulatus ranging from soft to very hard.
Well, unless you can provide a link and show me otherwise......I think you are mistaken.
Alf Stalsberg certainly did take water chemistry measurements for a Green Terror. But it is for the fish he was named after.
Andinoacara stalsbergi. As in the link here
http://www.senckenberg.de/files/con...z59-2/02_vertebrate_zoology_59-2_musilova.pdf Five measurememnts are cited that Alf Stalsberg took for the newly described
Andinoacara stalsbergi. All showing very hard to extremely hard water chemistry. Some of that info was already available elsewhere, previous to this classification in 2009.
The cichlidae.com profile on Andinoacara
rivulatus http://www.cichlidae.com/species.php?id=4 has been availabvle to all for at least 5-6 years now. Previous to reading it, I thought as you did, that the common GT (
A. rivulatus) came from harder water. I searched and searched .....and found nothing contrary. I realized that it is just part of the confusion that came about previously, with more then one fish being called a Green Terror, and the wrong species thought by aquarist to be the 'real rivulatus'.
Bear in mind that previous to
A. stalsbergi getting described in 2009, Alf stalsberg and the rest of the hobby wrongly thought and called this fish
Aequidens rivulatus. The 'real rivulatus' was being called
Aequidens sp. 'goldsuam". Also, initially for a brief period, Alf Stalsberg didn't accept the new classification, and was calling
Andinoacara rivulatus by one of it's synonyms (
Andinoacara aequinoctialis) possibly further adding to the confusion.
The paragraph in the cichlidae.com profile describing the water measurements taken for
A. rivulatus implies that many measurements were taken through out the range of the fish. "At most 1* dGH" is extremely soft water. I believe the notion of the common GT (
A. rivulatus) originating from hard water stems from the confusion over names in the past and more then one fish being called Green Terror.