There are several ways to remove a fish smell from a house, including spraying room deodorizers, brewing coffee and opening the windows to allow fresh air to circulate. If the fish odor is coming from the garbage disposal due to recently disposed fish, this can be remedied by grinding up lemon or orange peels in the disposal.
Simmering potpourris also help to minimize fish odors and can be easily prepared with simmering hot water, cinnamon, citrus peels and nutmeg. If the odor is strongest in the kitchen, placing a running fan near an open kitchen window helps to push the odors out while drawing in fresh air. Placing a bowl of vinegar on the counter top while cooking fish helps to absorb the odors before they build up in the room, minimizing the chances of lingering fishy odors.
In addition to lemons, apples also work well to minimize fish odor. Placing one or two sliced apples in the frying pan prior to cooking the fish dramatically reduces fish smell. The apples soak up the odor without leaving flavor on the fish. Fish is odorous, because it contains multiple amino acids. The moment a fish starts to decompose, bacteria begin to attack its flesh. While all fish has a slight odor, an overly "fishy" smell typically points to spoilage.