The figures you need is 17.08 German degrees (call it 17) This is the same as dH. The other unit used in fishkeeping is ppm, and 17 dH converts to 300 ppm. It is very hard water.
The only way to reduce the hardness is by mixing your tap water with pure water such as reverse osmosis (RO) water. Half and half will give you a GH (hardness) of 8.5.
Livebearers are among the more colourful fish and are ideal if you want lively colourful fish.
Research any fish before buying. Fish shops are notorious for poor advice. The best place is https://www.seriouslyfish.com/knowledge-base/ looking in particular at the hardness the fish requires and the size of the tank, particularly the length. Since you need to cycle the tank before you can get fish, you have plenty time to research.
The only way to reduce the hardness is by mixing your tap water with pure water such as reverse osmosis (RO) water. Half and half will give you a GH (hardness) of 8.5.
Livebearers are among the more colourful fish and are ideal if you want lively colourful fish.
Research any fish before buying. Fish shops are notorious for poor advice. The best place is https://www.seriouslyfish.com/knowledge-base/ looking in particular at the hardness the fish requires and the size of the tank, particularly the length. Since you need to cycle the tank before you can get fish, you have plenty time to research.