Ive seen and heard both. Is it like the other puffers where while they survive in fresh the will thrive in brackish water? I'm happy to set up a brack tank if thats whats best. But if they really are FW the BW will kill'em
No pygmy puffers are a fresh water puffer. I have heard rumours that they can survive for quite awhile in brackish, so I tried them in my brakish tank just to see, two became food for my Fahaka puffer and the other one died a few days later.