Help! My brother poured a large amount of fish food in my fish tank.?

My older brother doesn't care about fish and when I told him to feed the fish he poured a large amount of food in my tank. When I told him that over feeding is bad he said that it was good so that the fish will be fat. I know that's not true because overfeeding can make my tank cloudy but there is nothing I could do, the food sank into the bottom of the tank and I have no bottom feeder but the janitor fish which is always hiding. My substrate is sand not gravel so its hard for me to clean my tank. I have a filter but it only filter for a short distance and the other food is out of reach. The water is not yet cloudy but I better clean it before it gets cloudy but I'm not gonna put my hands there because the fish might be scared and become stressed. What should I do?