pica_nuttalli
don't be a twit
patriot, i imagine that the reason your violet goby has done well in freshwater is the fact that (as you mentioned in a post elsewhere) your water is very hard and contains a high mineral content.
brackish water contains many different dissolved mineral salts as opposed to just NaCl (table salt). for this reason, many fish which do best in lightly brackish water also do well in water which is just quite hard--the biggest difference between the two conditions is the absence of NaCl.
soft water, on the other hand, is lacking in dissolved minerals of any sort and thus is not an appropriate substitute condition for keeping lightly brackish fish. the aforementioned problems of chronic infections and decreased vitality will invariably become a problem and result in the premature death of the fish.
brackish water contains many different dissolved mineral salts as opposed to just NaCl (table salt). for this reason, many fish which do best in lightly brackish water also do well in water which is just quite hard--the biggest difference between the two conditions is the absence of NaCl.
soft water, on the other hand, is lacking in dissolved minerals of any sort and thus is not an appropriate substitute condition for keeping lightly brackish fish. the aforementioned problems of chronic infections and decreased vitality will invariably become a problem and result in the premature death of the fish.
that was a lot of vitriol. besides, there are species profiles and a search function to help people learn how to care for their fish. if that doesn't cover it, then you really ought to just start a new topic because obviously there's something unique about your situation.

lol interesting info, however ive always thought of them as a brackish water species and have seen evidence of such a claim 1st hand.