Ring your local council and they can tell you if there is chlorine in the water supply. If there is you should use water conditioner as it will neutralize the chlorine, monochloramine,dichloramine and trichloramine, all of which are disinfectants and therefore not good for fish. Put stress coat down to experience and try to avoid buying stuff from the pet shop that you don't realy need and you will have more money to spend on good stuff like fish or plants.