bloodworm

Bloodworm is the common name for the larval stage of certain non-biting midges in the family Chironomidae. The larvae are typically red or reddish, a coloration resulting from high concentrations of a hemoglobin-like pigment that enables them to uptake and transport oxygen in low-oxygen sediments. Bloodworms occur in freshwater and occasionally brackish habitats around the world.

Adult midges emerge from mud or shallow water after pupation. The larvae live in soft sediment in ponds, lakes, streams, and wetlands, often where organic matter accumulates. They are detritivores and microalgae feeders, using their specialized mouthparts to consume fine particles. Many species tolerate hypoxic conditions, contributing to the breakdown of sedimentary organic material.

Bloodworms undergo complete metamorphosis: egg, larva, pupa, and adult. The larval stage lasts weeks to months depending on species and temperature. Larvae pupate in the sediment and later emerge as adults, small delicate flies that resemble mosquitoes but do not feed much, if at all.

They are widely used as fishing bait due to their size and movement. They are also indicators of nutrient-rich, oxygen-poor waters. In polluted or eutrophic waters, high densities can affect fish populations and water quality, while their presence supports important aquatic predators such as fish, birds, and other invertebrates.