Sometimes known as the “red earthworm”, Lumbricus rubellis is a species of earthworm that was originally native to Europe and the British Isles, but has been introduces worldwide. Like other earthworms L. rubellus lives in soils high in organic matter and is a saprophage, which feeds on organic material.
Also known as the sewage worm, the sludge worm is a species of tubificid oligochaete worm which inhabits the sediments of lakes, rivers, and occasionally sewers worldwide. T. tubifex will ingest sediments for nutrition, selectively digesting bacteria and absorbing molecules through their body walls. Sludge worms can survive in areas with very little oxygen by waving their hemoglobin-rich “tail ends” to exploit any available oxygen, they can also exchange oxygen and carbon dioxide through their skin like frogs. They are also known to survive in heavily polluted areas that most other species cannot endure. If that wasn’t enough they can also survive drought and food shortage by lowing their metabolic rate and forming a protective cyst. This encystment may also function in their dispersal.