Tubifex is a cosmopolitan genus of tubificid annelids that inhabits the sediments of lakes, rivers and occasionally sewer lines.

[citation needed] Although the Tubifex worms are hermaphrodites, the male and female organs become mature at different times; thus self-fertilization is avoided, and cross-fertilization is encouraged.

When worms come to the surface due to lack of oxygen, they are collected and washed under brisk stream of water to remove residual mud attached to their bodies.

This risk can be partially solved by keeping the worms under brisk running water until they have voided the contents of their digestive systems.

[citation needed] Lastly, in poorly cleaned aquaria, Tubifex can become established as a pest species, covering the bottom of the aquarium in a thick carpet which may be considered unsightly.

[citation needed] In 2009, a large blobby mass made of colonies of Tubifex was found to be living in the sewers of Raleigh, North Carolina.

Revealed by a snake camera inspection of sewer piping under the Cameron Village shopping center, videos of the "creature" went viral on YouTube in 2009 under the name "Carolina poop monster".