Okay so I used to have Goldfishes but they died now I have Tiger Barbs. Now this is my 2nd set of tiger barbs. My first set died when I did a water change. I checked the tap water from the water change and it clears out with 0.3-0.5 ammonia, 0 nitrite, 0nitrate, and PH lvl of 7.6 from the TAP. I usually add a few small drops of Prime Conditioner matching the temperature of the tank. Water change is usually 30% and when I did it the first time they died instantly. So, my 2nd set just died after having them for 2 weeks and did a water change only for them to die again. This time I added a PH reduction chemical about 1/3 capsize to see if they were just having hard trouble breathing but NOPE, they died too. So I am curious on what I am doing wrong. Any tips will help out thanks.