Fruit Flies, Drain Flies or Fungus Gnats: How to Tell

Start by noting where the insects appear. Fruit flies favor fermenting food, fungus gnats favor damp potting soil, and drain flies favor organic film inside drains; their body shapes offer additional clues.

Trace the origin

Move an indoor plant gently: tiny flies rising from the soil suggest fungus gnats. Flies around old fruit or sticky recycling suggest fruit flies. Fuzzy insects resting by a sink or floor drain suggest drain flies.

Look at the body

Fruit flies are compact, often tan or brown, sometimes with reddish eyes. Fungus gnats resemble small, long-legged mosquitoes. Drain flies look somewhat like tiny moths with fuzzy triangular wings. Use a close photograph for comparison.

Treat the correct source

For fruit flies, wash bins and remove fermenting debris. For fungus gnats, correct consistently soggy potting mix and monitor with yellow sticky cards. For drain flies, scrub the organic film from accessible drains and check for leaks. Avoid indiscriminate pesticide use.

Frequently asked questions

Will pouring bleach down a drain solve drain flies?

It may not remove the breeding film. Physical cleaning matters more, and household chemicals must never be mixed.

Related: how to get rid of gnats in kitchen.