Is it true that you are not suppose to add bottled water when setting up a tank-say for a betta? I heard that the 'lack of minerals and other elements' hurt the fish, or is this a silly myth out there?
No, I have heard that too. I think that tap water has good dtuff in, but for some reason I think it;s good for plants but that it doesn't matter too much for fish.
Think it's cause of osmosis, so it depends on the kind of bottled water it shouldn't be distilled, cause then the osmosis thing brings to much water into the fishes cells