How to Raise Blackworms

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Blackworms (Lumbriculus variegatus) are a species of annelid native to North America and Europe. Blackworms are raised to provide live food for aquarium fish, or they are cultured for use in scientific experiments. Whatever your purpose for them, blackworms are easy to raise with a good aquarium setup.

Establish an Aquarium for Your Blackworms

Step 1

Use a glass aquarium for your blackworm habitat. A tank with capacity of 5 to 20 gallons is suitable, depending on how many blackworms you want to keep. Blackworms do better in shallow water, so choose a long aquarium over a tall one.

Step 2

Place your aquarium where it will receive daylight. You do not need supplemental light for a blackworm aquarium.

Step 3

Add a layer of aquarium gravel substrate to your aquarium. Use at least 2 inches of gravel since blackworms like to burrow through the substrate. Because of this, an under-gravel filter isn't advisable.

Step 4

Fill the aquarium until the water is 5 inches deep, then set up the filter. A corner filter attached by suction cups beneath the water level is best.

Step 5

Set up the air pump and add an air stone to your aquarium.

Step 6

Keep the water at room temperature. Temperatures above 85 degrees may kill your blackworms.

Step 7

Allow the filtration system to run for 24 hours.

Caring for Your Blackworms

Step 1

Remove your blackworms from the container in which you received them and place them in a plastic container with just enough dechlorinated water to cover them. Swish the worms around in the water, dump out as much as you can, and refill with more water. Repeat this process until the rinse water is clear. The worms are now ready to add to the prepared aquarium.

Step 2

Feed your blackworms every other day. In the wild, blackworms are detritivores, eating any organic material they can easily nibble. Fresh produce like cucumber or grapes, as well as fish food, make suitable food for your blackworms. Feed them only as much as they will eat between scheduled feedings.

Step 3

Perform water changes weekly. Remove 50 percent of the water and replace it with fresh dechlorinated water. Between water changes, check the water level and refill as necessary to make sure the filter remains covered. Worms crawling out of the water and up the sides of the tank is their way of telling you they need fresh water pronto.

Items you will need

  • Glass aquarium
  • Gravel
  • Dechlorinated water
  • Corner filter
  • Air pump
  • Air stone
  • Plastic container
  • Blackworms
  • Fish food, fresh produce, or other food
  • Turkey baster or pipette

Tips

  • A pH level of 7.0 is ideal for blackworms.
  • Although you can use materials like shredded paper or leaves as substrate for a blackworm aquarium, gravel is the easiest to clean.
  • Don't bother cleaning algae that grows on the sides of your aquarium -- it serves as a food source for your blackworms.
  • Cultured blackworms reach sizes of just 2 to 3 inches long and never sexually mature. Wild-caught blackworms may be as long as 5 inches; they may reach hermaphroditic sexual maturity.

Warning

  • Remove any dead blackworms from the aquarium immediately. Ammonia released from a decomposing blackworm can quickly throw off water quality and negatively affect the remaining population. Dead blackworms float, so they're easily spotted and removed from the aquarium. Use a pipette or turkey baster to remove dead blackworms.

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    Author

    Madeline Masters works as a dog walker and professional writer. In the past she has worked as a fitness columnist, fundraising copywriter and news reporter. Masters won two Pennsylvania Newspaper Association Awards in 2009. She graduated from Elizabethtown College with a Bachelor of Arts in English.