Oh and also touching on the puffer fish concept, assuming you are referring to fish such as the green spotted puffer, all of them do live in freshwater, every single one of them for as long as they have been on this earth. Not saying they will stay there for the entirety of their lives, but fresh is where they spawn. So not to sound like a jerk, but that point is moot regarding the puffer fish comment, because they do in fact live in freshwater at least a fraction of their lives. I think others will agree with that point as well.