How do rainbow perch sleep?

i caught 3 rainbow fish today, and put them in my tank, im wondering now why they are just laying on the bottom of the tank, i know they cant be dead, because dead fish float.... are they tired? one is laying over on its side right now, and its gills are moving and every now and then it will start swimming around, i hope the chlorine in the water didn't hurt them :( and i dont have a filter yet.