Bloodworms For Fish: The 3 Types You Need to Know


While they are not exactly popular or well-known, bloodworms are one of the most beneficial types of live fish food. They are easy to culture, nutritious, and cost-effective to buy, which makes them an ideal addition to your fish’s diet. There are many different types, but most are similar enough to be used interchangeably with minimal effect on your fish.

There are three types you should learn to recognize: live, frozen, and freeze-dried bloodworms. All of these options can be effective when it comes to feeding your fish but have different qualities that make them suitable for different uses.

Let’s take a look at the main differences between the three to find out which one you should use and why.

What are bloodworms?


They are larvae typically found in freshwater pools and ponds. They are farmed on the northeastern coast of the U.S.

The bloodworm is a popular bait for fishing and is a food for freshwater fish worldwide. While almost every fish species will eat them, it is essential to remember the importance of a varied diet. They are an excellent source of protein, so they should be given to your fish regularly.

They are laxatives (think of them as an All-Bran for fish). Often, fancy goldfish with too much-dried food suffer from constipation, and feeding them bloodworms regularly helps them keep in shape.

Where do bloodworms come from (Origin)?

The northeast coast of America is home to various types of bloodworms that are usually found in freshwater pools and ponds. Worldwide, they are used as bait for fishing and as food for freshwater fish.

Types of bloodworms

There are 3 main types, which are live, frozen, and freeze-dried bloodworms.

Live bloodworms

Among the options aquarists consider are live bloodworms. Buyers tend to prefer this over frozen food because the worms are alive (obviously) and they give fish food more naturally.

Vernal Pool Fairy Shrimps (Anostraca)


  • Compared to freeze-dried or frozen, they are usually fresher.
  • Their vitamin and nutrient content is much higher than that of other types.
  • Fish that are fed live bloodworms perform much better than those that are fed flakes (due to the fact that they are more active).
  • During the “conditioning” phase of breeding, these tubs can be useful. This can be accomplished by providing them with nutrient-rich food.


  • Their storage life is not as long as that of other forms. The most suitable time to use them as food is usually two or three days before they die.
  • For them to be ready to eat, a little more prep work is necessary.
  • The animals that eat live worms are at increased risk of contracting diseases and illnesses.

Freeze Dried Bloodworms

Most tank owners use freeze-dried bloodworms since they are convenient and common.


  • They are definitely easy to feed to fish.
  • It allows you to have more control over how you feed them because they are available in different quality grades


Frozen Bloodworms

A large majority of aquarists prefer frozen bloodworms. Convenience plays a huge role in this, but here are some of the advantages and disadvantages you should know:


  • It is possible to store them in your freezer for nearly half a year
  • Fish can eat them without fear of contracting diseases because they are extremely low in risk.
  • By feeding frozen bloodworms to your aquarium, you can either concentrate them in one area or spread them evenly throughout it.


  • Feeding time will be less active.
  • When feeding frozen bloodworms, you must wait for them to thaw.
  • Due to the fact that 100% of the frozen bloodworm will not be eaten, it can increase the bioload in your tank.
Ghost Shrimp (Palaemonetes paludosus)

How big do bloodworms get?

They can grow up to 15 inches (37 cm) in length.

How do bloodworms reproduce?


It is during midsummer when sexually mature worms undergo a transformation into a non-feeding state called the epitoke, which is triggered by a combination of factors, including warmer water temperatures and the lunar cycle. Both sexes release gametes at the surface of the water with enlarged parapodia.

Most of them begin their lives as zooplanktonic larvae that develop into segmented red larvae when they reach their benthic instar.

Over a period of as little as 2 to 3 weeks in optimum conditions, these larvae progress from pale opaque worms to red larvae that are 6 to 12 centimeters long or longer.

What do bloodworms eat?

They are carnivores. Their proboscis bears four hollow jaws that allow them to feed. Having venom glands in their jaws allows them to kill their prey with venom, an attack that can even be painful to humans.

Which fish can you feed bloodworms to?

They can be fed to most bottom-feeder fish such as flatfish like flounder, halibut, sole, and plaice, cod, eels, haddock, grouper, bass, carp, bream (snapper), and some species of catfish and shark.

Why are they unique?


Copper is in abundance in these animals without poisoning them. Unlike other animals, their jaws contain copper-based chloride biominerals, known as atacamite, in crystalline form, which explains their unusual strength. According to theories, copper is responsible for its venomous bite. Melanin and copper are both present in the jaws of Glycera dibranchiata.

Why do bloodworms have copper teeth?

With sharp, metallic jaws, they fight off their enemies and defend themselves using protein, melanin, and copper. Bloodworms’ jagged jaws are composed of jagged pieces of metal, but how they are made has been unknown for a long time.

Bloodworms bite

A bloodworm bite is similar to a bee or wasp sting. Those creatures eat small crustaceans, and their venom can stop their hearts, but it can’t hurt humans. However, it can occasionally cause severe allergic reactions, similar to those caused by bee stings.

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How long will they stay alive?

Their average lifespan is around 2 to 7 weeks.

Reasons to keep bloodworms in your aquarium

  • Your fish will spawn faster if you use them.
  • They are an excellent protein source for carnivorous fish.
  • Anemia in aquarium fish can be treated with bloodworms because of their high iron levels.
  • Through their consumption of decaying matter, bloodworm larvae help maintain clean tank water.