I've read mixed things but are south american puffers (Colomesus asellus) strictly fresh or do they eventually need brackish conditions?
I agree.C.Asellus as far as i know has always been 100% F/W fish unless documents have been updated in recent years to say otherwise?
However T.Fluviatilis (AKA Ceylon Puffer) that looks similar is a puffer that requires high end brackish to marine as adults which maybe where the confusion comes from...
The Masked Shadow there are actually a lot more F/W puffers than what you listed including a few red eye species such as C.Salivator, C.Irrubessco and also species such as T.Miurus, T.Baileyi among others...
I had one 4 years ago.. regret letting it go.. glad I'm getting another one. They are so personableFahakas are definitely fun puffers to keep, not too small and not overly large...