Moth Fly (Drain Fly)

Natural Habitat

Moth flies are commonly found in humid environments rich in decaying organic matter, such as bathrooms, kitchens, basements, and sewage treatment plants. Specifically, they infest drains, sewers, septic tanks, and any place where stagnant water and organic sludge accumulate.

Diet & Feeding

Larvae feed on decaying organic matter, fungi, algae, and microorganisms found in the slimy buildup of drains, sewers, and septic tanks. Adult moth flies do not typically feed.

Behavior Patterns

Moth flies are often seen resting on walls or other surfaces near drains, sinks, or humid areas. Their flight is weak and erratic, characterized by short, hopping movements. Larvae and pupae develop in the gelatinous film found in drains and pipes, feeding on organic matter. Adults are short-lived, typically for only a few days, and do not feed. They are primarily active at night and are attracted to lights.

Risks & Benefits

Risks: Moth flies are generally considered nuisance pests. While they do not bite or transmit diseases, large infestations can be bothersome. They can also indicate underlying sanitation issues in plumbing systems, as their presence means there is significant organic buildup. In rare cases, larvae or eggs might be ingested, leading to accidental myiasis, though this is very uncommon. Benefits: They play a role in decomposition by consuming decaying organic matter, helping to break down waste in their habitats.

Identified on: 6/24/2025