According to the "Five Elements with Five Flavors" in Lu's Spring and Autumn Annals, the smell belongs to wood, the burnt belongs to fire, the fragrant belongs to earth, the fishy belongs to gold, and the rotten belongs to water.
The smell that flies like is fishy, so it belongs to gold.
Azimuth, the golden direction is west, the Golden Gate is wide open, and insects are moved by it.
According to the principle that the five elements coexist, wood can damage gold, and fire can gram gold.
Therefore, if this matter must be based on geomantic omen, the way to avoid flies is to put potted plants in the west of the home and hang red knots in the west of the home.
(Haha, for reference only. )