Drain Fly Larva

Natural Habitat

Found in moist, organic-rich environments such as the gelatinous slime lining bathroom drains, sewers, septic tanks, and wet compost.

Diet & Feeding

Feeds on organic matter, algae, bacteria, and fungi found in the biofilm or slime of drains and plumbing.

Behavior Patterns

Larvae live within the slime layer and breathe through a small siphon. They undergo pupation in the same habitat before emerging as small, fuzzy, moth-like adult flies. They are most active in stagnant or infrequently used drains.

Risks & Benefits

Generally harmless to humans and do not bite. They can be a nuisance in large numbers. While they help break down organic matter in sewage, they can potentially transport bacteria from drains onto household surfaces.

Identified on: 3/29/2026