Earthworms and blackworms both travel by using contractions in their body which move each body segment in sequence; earthworms crawl and blackworms swim by using the same motions. Earthworms and blackworms both use natural camouflage to hide from predators, and hide when threatened. Blackworms stick their heads out of the sand to eat algae and microscopic creatures in the water. Worms survive on a diet of soil. However, they both retreat to their tunnels for safety.
Earthworms are commonly found in rich, moist soil. They spend their lives creating tunnels in the ground, coming to the surface when their tunnels flood from rain. Blackworms are aquatic, and spend their entire lives underwater. They are most commonly found in shallow ponds and calm, slowly moving bodies of water. Although these species live in different worlds, they both attempt to stay buried under soil or sand for most of their lives.
Blackworms live underwater and earthworms live on land, but both species have similar reproductive habits. Blackworms and earthworms are hermaphroditic; they have both male and female reproductive organs. Sexual reproduction is rare, and involves an elaborate mating process and the creation of a cocoon to create an embryo. Blackworms and earthworms primarily reproduce through asexual reproduction; worms cut into fragments will create multiple new worms. This can happen when a worm is injured, or by choice.
Worms are a common bait used in fishing. Earthworms are a commonly used bait because they are easy to find. Blackworms can be more difficult to collect since they live underwater, but both types of worms can also be purchased at bait shops. Earthworms and blackworms are also sometimes used as classroom pets, teaching children about different environments and biology. In nature, worms are food for larger creatures and are an important part of the ecosystem.