Fungus gnats are tiny, black flies that are commonly seen around lamps and windows. They are annoying, but harmless and do not harm indoor plants. The larvae breed in moist soil, primarily in potted plants containing soil rich in organic matter. Larvae feed on fungi in the moist soil.

Fungus gnats are little bugs that flutter up and around your indoor greenery, and show up whenever you water. They're tiny flies, about 1/8-inch long, drawn to moist potting soil and decaying leaves on the soil's surface around your plants. If you spot one up close, you'll notice that they look a little like tiny mosquitoes but don't bite.