As per puffergirl's message. "Amazon Puffers" and "Brazilian
FW Puffers," and "Peruvian Puffers" AND "South American Puffers" are ALL the same species (amazing isn't it!?!?), Colomesus asellus. If you do further research, Gregg, I think you'll find that most of the
FW puffers have 2-8 names, as they do on
http://www.pufferfish.co.uk/aquaria/index.htm I think the Dwarf Puffer wins in this category!
Though individual puffers of the same species can differ in temperament, it's probably best to think scientifically about the differing accounts that pop up. In MOST cases, puffers will be more peaceful in a large tank with conspecifics (members of their own species). In small tanks where they feel cramped, and alone, and indeed territorial, they will turn their aggression on other species. If they are in a pack, they are likely to be less territorial, more comfortable and more amenable. In this instance, and in a large enough tank, you can mix them with other hardy, fast fish such as Tiger Barbs.
So, if anyone tells you a puffer species is peaceful, take this with a spoonfull of salt. No puffer is peaceful unless it feels comfortable, and even the most aggressive species--such as the Green Spotted Puffers--can be pleasant enough if given plenty of room and some conspecific friends.
P.S. William, thanks for being a good sport! A lot of ppl just get mad when you correct them.