As some of you may have read I had a mysterious death of 1 of my newly added threadfin rainbows. I recently did a water change, and I'm not sure if this is just a coincidence but after a few days I have lost 3 rasboras, 1 more threadfin and unfortunately my little dwarf gourami 
This prompted me to go out and buy a more accurate testing kit, so I'll post them here in hopes some of you might be able to give me some kind of idea as to fixing my problem.
ph - 8.0
nitrIte - 0
Ammonia - 0
GH - 200+
KH - 70
My other fish look fine right now, in fact an hour before my gourami died he looked fine to me, he was swimming around normal, maybe a little bit slow but it was very early in the morning, when I came back he was dead on the bottom of the tank, he had a circular bloch on his side, and I can only compare it to maybe dry skin would look like. All the other dead fish had no signs of disease, nor did they show signs previous to their death that they were under any stress. Please help.
Cheers
This prompted me to go out and buy a more accurate testing kit, so I'll post them here in hopes some of you might be able to give me some kind of idea as to fixing my problem. ph - 8.0
nitrIte - 0
Ammonia - 0
GH - 200+
KH - 70
My other fish look fine right now, in fact an hour before my gourami died he looked fine to me, he was swimming around normal, maybe a little bit slow but it was very early in the morning, when I came back he was dead on the bottom of the tank, he had a circular bloch on his side, and I can only compare it to maybe dry skin would look like. All the other dead fish had no signs of disease, nor did they show signs previous to their death that they were under any stress. Please help.
Cheers
