I've been thinking of setting up a biotope tank for my F8 puffers, so I used the google to search about the subject and it is what I concluded:
Tetraodon biocellatus is mostly found in Mekong River (http://fish.mongabay.com/data/ecosystem ... 0River.htm) which is a long river that begins in the south of China and ends in the south of Vietnam.

Well, Tetraodon biocellatus comes from Southeast Asia (Myanmar, Laos, Thailand, Vietnam, Cambodia, Malaysia and Indonesia), so we have this:

I drew two lines: the red one shows where F8 would be very common and the purple one shows where F8 would be mostly found.
In such case, if someone would like to set up a low end brackish biotope for Tetraodon biocellatus, these are the options (the plants mentioned in these sites are brackish tolerants):
http://www.aqua-fish.net/show.php?h=indianburmeseriver
http://fish.mongabay.com/biotope_indian_river.htm
http://www.aqua-fish.net/show.php?id=8& ... &what=aqua
http://fish.mongabay.com/biotope_thai_creek.htm
Well, that is all I could find about F8 puffers' biotope. If I'm wrong, please someone corrects me!
Thanks everyone for your time to read this LONG text I wrote. Thank you.