What is the California blackworm?

The California blackworm is found in muddy sediments of shallow waters along the edges of ponds and marshes throughout much of the United States. The worms feed on dead and decaying vegetation, such as dead leaves and decaying wood, as well as algae and bacteria.

With no lungs or gills, California blackworms breathe through their skin, sticking the dorsal surface of their tail to the water surface to obtain oxygen. The worm's body typically consists of 150 to 250 segments and is able to regenerate a new head or tail from just a small fragment. Blackworms are commonly sold to pet owners as live food for aquarium fish.