Small-fly identification
Fruit fly vs fungus gnat vs drain fly
Tiny flies are not one kitchen fogger job. Fruit flies hover on fermenting produce. Fungus gnats run on wet potting soil. Drain flies rest on bathroom tile and breed in pipe film. Wrong source, infinite traps. This page is the decision path.
A simple decision path
- Are they on fruit, beer, or recycling?. Fruit fly. Hunt the film. Vinegar traps mop adults only.
- Do they run across houseplant soil when you water?. Fungus gnat. Dry-down the mix.
- Are they fuzzy, moth-like, and resting on bathroom walls?. Drain fly. Clean drain slime, not the fruit bowl.
- Do they scuttle with a humped back despite a clean kitchen?. Think Phorid fly and a hidden decay source — carcass or broken pipe — not produce.
Appearance, location, lifecycle
| Fruit fly | Fungus gnat | Drain fly | |
|---|---|---|---|
| Look | Tiny tan, often red eyes, hover | Delicate, long-legged, dark, weak flight | Fuzzy, heart-shaped wings, hop |
| Where you notice them | Fruit bowl, bar, compost crock | Pots and nearby windows | Shower tile, floor drains |
| Breeding site | Fermenting pulp and sugar film | Wet potting media, larvae with black heads | Gelatinous pipe film, not the water you see |
| Generation speed | Very fast in warm kitchens | Continues while you overwater | Continues while slime remains |
| Wrong tool | Fogging produce | Kitchen fogger | Weekly bleach as a personality |
Species pages
Each species article has the control sequence and safety notes. This page only splits look-alikes.
Fruit fly
Drosophila spp.
Fruit flies are tiny tan flies with red eyes (often) that breed in fermenting film: a potato in a crisper, a…
Fungus gnat
Sciaridae / Mycetophilidae (sciarid types in pots)
Sciarid fungus gnats are weak fliers around pots, not a cloud over a fruit bowl. Larvae live in the top inch…
Drain fly
Psychodidae
Drain flies are fuzzy, moth-like, weak fliers that rest on bathroom walls. They breed in the gelatinous film…
Common questions
I cleaned the fruit and they remain. Why?
Missed source, or they were never fruit flies. Check plants and drains.
Can one trap type catch all three?
No. Vinegar cups do not treat soil larvae or drain film.