Quote Originally Posted by Jessika
That's true; its called cross-contamination. Though if a fish is diseased to begin with, it will transfer to the tank regardless.
Soo i shouldn't be using store water, i do put the water purifier in it. Our water is well water the has some copper in it that has killed several betta fish. I have had my betta fish two weeks with the store spring water and it is very healthy!