Earthworms belong to the phylum Annelida which are the segmented worms. Their digestive system takes up the full length of their bodies and they breathe through their skin.
There are a few different species of worms used in composting. They are generally smaller and red in colour.
The four main species of earthworm used as composting worms:
Tiger worm (Eisenia fetida) / Blue noses (Dendrobaena venta) / Red wiggler (Lumbricus rubellus) / Red tiger worm (Eisenia andrei)