Hi and welcome to the forum
If you can contact your water supply company (via website or telephone) and find out what the general hardness (GH), carbonate hardness (KH) and pH of your water is, that will help when it comes to getting fish suited to your conditions.
If the water company does not have this information, take a glass full of tap water to the local petshop and ask them to test it for you. Write the results down (in numbers) when they do the tests. And find out what the results are in (eg: ppm, dGH). Then post the results here.
The next time you visit the petshop, make a list of fish and plants that you like and post it here along with the water test results, and the dimensions (length x width x height) of your aquarium. We can go through the list and make suggestions on what fish will go with each other and be suitable for your water chemistry and the tank.
You can also check out different substrates like sand and gravel and post the info here. Some gravel is not suitable for some types of fish.
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The following link has information on what to do if your fish gets sick. It's pretty long and boring but worth a read when you have some spare time.
http://www.fishforums.net/threads/what-to-do-if-your-fish-gets-sick.450268/#post-3804819
