Exactly. Chlorine will leave the water after about 24 hours of aging, but chloramine will not. That's exactly why chloramine was developed to be put in drinking water, to keep it 'cleaner' for longer periods of time. Pretty much no matter where you live, you'll have both in your tap water, so you'll have to use a dechlorinator/dechloraminator. Wherever you buy aquarium supplies will have something to use, you can just ask them.
If you don't remove chlorines and chloramines from your water, your fish won't last very long. It directly affects them because it is physically bad for them and for their skin. Indirectly, though, it kills beneficial bacteria, the kind you want in your tank because they get rid of dangerous chemicals like ammonia and nitrite, which will allow these dangerous chemicals to build up and either kill your fish or render them susceptible to disease.