i guess i learn something too then. i always thought they were but i looked it up and found this article.
Bloodworms are the larval form of the Chironomidae group of Midges. These look similar to mosquitoes, but they do not bite. In fact most of them do not even eat while in the adult form. The adults only live for a short time, mating at night, and the female laying her eggs into the water while flying low over the surface.
The eggs hatch into a creature than looks like a worm although some people object to the name Bloodworm because they have an exoskeleton and little legs.
They are red which is what gives them the blood part of their name. This is caused by the presence of a form of Haemoglobin. Naturally it is not identical to Human Haemoglobin, but it is also an Oxygen carrying pigment.
The Bloodworm lives near the surface of the sediment at the bottom of ponds and streams, eating the decaying plant material.
Bloodworms are very tolerant of pollution, and will live in quite dirty water that Humans prefer to stay away from.
Bloodworms can be present in very high concentrations.
Bloodworms are good food to many things including fish and predatory insects. The Bloodworm is partially protected by the sediment they live in, but they are vulnerable when they come to the surface to change into adults. At this point of their life, many get eaten by fish.
Although I have lumped them together under their common name, there are hundreds of different species of bloodworm that have been scientifically described, and possibly thousands that have not yet been described.