Drain fly (larva)

Moist environments containing organic matter, such as drains, sewage treatment plants, septic tanks, and compost piles.

Decomposing organic matter, algae, bacteria, and fungi (as larvae).

Larvae live in the gelatinous film that forms inside drains. They are generally nocturnal as adults and poor fliers, often seen resting on walls near drains.

Generally harmless to humans but can be a nuisance in large numbers. In some cases, they can mechanically carry bacteria from sewage to food surfaces, though they do not bite or transmit blood-borne diseases.