The GH is general or total hardness which is the measure of dissolved calcium and magnesium in the water. Other minerals are very low in domestic water supplies as many of them are toxic, so no worry here. Calcium is the prime mineral. At 0 there is very little to no calcium/magnesium in the water. This is ideal for soft and very soft water fish species but no good for livebearers, rift lake cichlids, some rainbowfishes.
GH is the most important parameter, along with temperature, for tropical freshwater fishes. Each species has evolved to function and live in very specific water. While there is some elasticity, more for some fish than others, there are species that absolutely must have these minerals in the water because they use them to function. There are also many fish species that can not have these minerals because they enter the fish's bloodstream and are caught by the kidneys, and in time the kidneys get blocked and the fish dies. So finding fish suited to your water is the first step in success.
Turning to the pH here, it seems very high (8 or above?) and it would be worth seeing if something is being added to the water to do this. With very soft water one would normally expect the pH to be acidic to neutral. Check the water authority's website, or call them. Areas that have very soft water with a natural pH that is acidic often have substances like soda ash added to raise the pH but not the GH or KH. The KH is also high, and this will buffer the pH preventing it from fluctuating, which is fine, but it will keep the pH high. This carbonate hardness can be removed by boiling the water. I've never done this, but I mention it.