Bloodworms are the bright red larvae of the Chironomus midge, a non-biting bug that resembles a mosquito. Bloodworms are a high protein treat for your pet fish, but most aquarium owners recommend buying them frozen rather than trying to raise your own. If you are determined to start cultivating your own bloodworms, you will need to experiment.
Collect midge eggs from the water of a lake or pond. The eggs (50 to 700 tiny dots) will be in clear, jellylike clumps or tubes attached to the twigs and grasses along the shoreline.
Set up the eggs in containers filled with room-temperature, non-chlorinated water, placed away from sunlight. The eggs will hatch within 48 hours. Bloodworms grow fastest in a dark, well-aerated environment. Providing the water with plants and mud will help to create a good ecosystem. Try as many as six different containers with varying numbers of eggs.
Feed your larvae. Bloodworms eat the microscopic matter of dead plants and animals. If you have recreated an ecosystem in your container with plants and mud or compost, this may be enough to keep your bloodworms fed. You can also purchase micro-foods from a commercial vendor or do as the professionals do (per Aqualand Pets Plus) and feed manure to your bloodworms. Keep records of how much of each food you are feeding your bloodworms to track what works best.
Harvest most of your bloodworms before they pupate. The complete life cycle of the bloodworm is 10 to 12 days. You can add some of them directly to your fish tank, but the excess should be put in the refrigerator or freezer for later feedings.
Allow some of your bloodworms to pupate into adult midges. The larvae turn to pupa, which will need to burrow into mud. A couple of days after they have disappeared into the mud, the pupa will swim to the surface and emerge as midges. Midges live up to five days, never eating. They mate, lay eggs and die. Keep the container you will be using to cultivate adult midges uncovered and somewhere where you will not mind having a cloud of midges for a few days.
You may need to try a few different approaches to your bloodworm farm before you discover what works best. Hobbyists dismiss the raising of bloodworms as too difficult, so be prepared for a challenge.
You may cultivate some mosquito larvae in your uncovered containers. Bloodworms are up to an inch long, bright red and swim by wriggling in a figure eight. Mosquito larvae are only a half an inch long, moult four times during their larvae cycle and come to the surface often to siphon oxygen through a tube on their back end. Mosquito larvae can be fed to your fish as well, but it's best not to let them pupate into adults.