says that the filter cleans the water, so its like the fish are always taking a bath, and so they're always clean every day. i wish there was a filter like that in my bedroom. then it would filter the air, and i would always be taking an air bath and i would never have to take one in the bath tub again. but i bet it would be kind of loud. the filter i mean. the one on the fish tank makes noise all the time. i wonder if it makes it hard for the fish to sleep. i never see them sleep, not once. even though one time 