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Bloodworms 101: The Ultimate Guide to Feeding Your Aquarium Fish

If you’re looking for a tasty and nutritious option for your carnivorous or omnivorous fish, look no further than the mighty bloodworms. These tiny, wriggling creatures are packed with protein and essential nutrients, making them a popular choice among aquarium enthusiasts and anglers alike.

But what exactly are bloodworms, and why are they so important for your aquarium? In this guide, we’ll take a closer look at these fascinating creatures, explore their nutritional benefits, and show you how to incorporate them into your fish’s diet for optimal health and vitality.

So, let’s dive in and discover the wonders of bloodworms!

What Are Bloodworms?

Bloodworms are the larvae of non-biting midges and are commonly used as a food source for fish and other aquatic animals. There are two types of bloodworms found in aquatic environments: Glycera and Chironomidae. However, it’s important to note that Chironomidae is not actually a worm but rather the larval stage of the non-biting midge.

Bloodworms, whether of the Glycera genus or from the Chironomidae family, get their red coloring from the iron-porphyrin protein in their tissue and blood. They can survive in environments with lower oxygen concentrations due to the high concentrations of hemoglobin in their blood.

Where to Find Bloodworms: Their Habitat and Distribution

Bloodworms can be found in various aquatic environments around the world. Chironomid larvae, one type of Bloodworm, are commonly found in freshwater habitats like pools and ponds across Europe, Asia, North America, and even in Antarctica, while the other type, Glycera, are found in saltwater, specifically in intertidal zones along coastlines. They are particularly abundant in the Northeast region of the United States.

How to Identify Bloodworms in the Wild

Bloodworms are distinguishable by their pink or dark red color and are typically thicker at the head. While they can grow up to 14 inches (35cm), this is rare as they are typically harvested at a younger, smaller size for use as fish food.

Glycera, found in saltwater environments, are typically covered in mud and require cleaning before identification. They can also bite, so caution is advised.

Chironomid larvae come in various colors and have unique features like banding and sclerotized head capsules that can be observed under a microscope to differentiate them from one another.

The Nutritional Value of Bloodworms for Fish

Bloodworms are a great source of protein for your fish and are rich in iron. However, since they have a limited range of amino acids, they are not suitable as a sole food source. It’s crucial to provide your pet fish with a balanced diet.

Feeding your Betta pair a bloodworm diet has been proven to be particularly beneficial for breeding. Researchers found that more eggs were produced by spawning Bettas fed on bloodworms compared with other foods, including commercial fish food and Artemia cysts (1).

Frozen bloodworms and bloodworm gels often have added minerals, including beta carotene, which enhances the vibrant colors of Bettas and other tropical fish, as well as B12.

NutrientAmount per 100g
Vitamin C5.5mg
Vitamin B120.13mg
Vitamin A (as Beta carotene)0.16mg

Types of Fish That Can Benefit from Bloodworms

Bloodworms can be a great addition to the diet of most carnivorous or omnivorous fish. Some of the aquarium fish that love to eat bloodworms include:

  • Betta fish
  • Goldfish
  • Guppies
  • Mollies
  • African cichlids
  • Platy fish
  • Kuhli and Clown loaches
  • Discus fish

Other aquatic animals that enjoy bloodworms include Frogs, Crabs, Shrimp, Crayfish, Salamanders, Turtles, and some species of Snails (Assassin Snails, Trumpet Snails, and Malaysian Trumpet Snails). However, herbivorous fish (that require a diet of plant matter) shouldn’t be fed bloodworms.

Types of Bloodworms for Pet Fish

There are four types of bloodworms for pet fish: live, freeze-dried, frozen, and gel-based.


When you feed your fish live bloodworms, it simulates their natural feeding habits in the wild. Your fish’s predatory instincts will come into play, and it’s a thrilling experience to watch your Betta feed this way.

Live bloodworms are best sourced from a Bloodworm farm or a trustworthy pet store, but you can also grow them yourself. If you purchase them, they should be kept for no more than two or three days and stored in a container with water at the bottom and a lid.

Although live bloodworms are healthy and enjoyable for your fish, they can also introduce parasites to your aquarium. Before feeding them to your fish, rinse the worms thoroughly, and limit live feeding to prevent any adverse effects. Live bloodworms should be a treat for your fish, not their primary diet.


Omage Frozen Bloodworms in Blocks

Frozen Bloodworm is sold in blocks making it easy to portion, and can be stored for up to six months.

The freezing process kills bacteria and parasites, so frozen Bloodworm is safer for your fish than live Bloodworm. And the freezing process preserves nutrients and protein, so it’s still a healthy meal.

Defrost frozen Bloodworm before feeding your fish. Adding frozen food to the aquarium can affect the tank’s temperature and sudden temperature changes can lead to shock.


Freeze-dried bloodworms are also available, and they come in tubs with a long shelf life. They are the most economical type of Bloodworm for your fish. The quality of freeze-dried Bloodworm varies depending on the grade, A or B. Grade B is less expensive but less nutritious, containing less than 100% Bloodworm. Check the label and buy from reputable brands to ensure high-quality food for your fish.

The freeze-drying process reduces the nutritional value of bloodworms, but around 90% of nutrients should remain. Although freeze-dried bloodworms are not as nutritious as frozen bloodworms, they are still an excellent option.

Before feeding your fish, soak the freeze-dried bloodworms. Feeding freeze-dried bloodworms can absorb moisture from your fish’s stomach. Adding dry food to the tank can also affect the water temperature, leading to shock in your fish.

Fresh Gel

To offer your fish an alternative to frozen, live, or freeze-dried Bloodworm, fresh gel Bloodworm is available. It has a long shelf life, up to 12 months, and is nutrient-dense, providing double the nutrients of freeze-dried and frozen Bloodworm (according to the manufacturer).

Fresh gel Bloodworm can be less appetizing for your fish. You can help by soaking it for a few minutes before feeding to encourage your fish to eat it.

How Many Bloodworms to Feed Your Fish and How Often

The recommended amount of bloodworms to feed your fish depends on their size and dietary needs. As a general guideline, it’s highly recommended to feed your fish an amount of bloodworms that they can consume in 2-3 minutes once or twice a week, alongside a balanced diet of other foods like Daphnia, Brine Shrimp, and Pellets designed to meet their nutritional needs.

Avoid overfeeding your fish as it can lead to health problems. Also, make sure to remove any uneaten food to prevent it from rotting in the tank.

Although bloodworms are a nutritious and protein-rich food for fish, they shouldn’t be the sole component of their diet. Some hobbyists use Bloodworm as a staple food while others use it as a treat.

How to Properly Feed Your Fish Bloodworms: Tips and Tricks

Preparing and Handling Live Bloodworms

When handling live bloodworms, it’s important to wear gloves to avoid bites and potential allergic reactions. Asthma has also been linked to handling the parent insect of bloodworms, Chironomid (2). Before adding live bloodworms to your aquarium, rinse them thoroughly to reduce the risk of introducing parasites. Remember not to add the water that comes with the bloodworms to the aquarium.

Tips for Properly Feeding Your Fish Bloodworms

If you’re having difficulty feeding your fish with bloodworms, there are a few tricks you can try.

  • Tongs can be used to hold the Bloodworm and bring it close to your fish, which can encourage feeding.
  • Alternatively, a plastic feeding cone can be used to keep the Bloodworm in one place in the tank, making it easier for your fish to locate and eat.

Typically, fish are fond of bloodworms and will readily consume them, but using these tools can help if you’re having trouble.

How to Grow Bloodworms at Home: A Step-by-Step Guide

Store-bought bloodworms are expensive and have a short lifespan of only a couple of days. With some guidance, it’s easy to cultivate your own bloodworms and harvest them as a nutritious food source for your fish.

Materials Needed for Bloodworm Cultivation

To cultivate bloodworms at home, you will need the following supplies:

  • Container with a lid to house the bloodworms
  • Soil to mix with farm manure to create a suitable environment for the bloodworms to grow
  • Rain, pond, or creek water to add to the mixture
  • Bloodworm eggs to hatch and grow in the container
  • Dead leaves to cover the eggs and provide additional food for the bloodworms

Setting Up Your Own Bloodworm Farm

Here’s how to set up a Bloodworm farm:

  1. Get an old bucket, an aquarium or a large plastic container. You will need a lid. Keep the container somewhere warm and sunny during the day, and prevent it from freezing at night.
  2. Add a mixture of garden soil and cow or chicken manure to your container in a 2:1 ratio, respectively. The mixture should be moist but not waterlogged, as that can harm the bloodworms.
  3. Add rainwater or water from a pond to the mixture, stirring it into a thick paste. Avoid using tap water as the chemicals can kill the bloodworms.
  4. Place the Bloodworm eggs in the container. You can collect eggs from freshwater environments or buy them from sellers.
  5. Add a layer of dead leaves on top of the eggs, about an inch thick, to protect them and provide an additional food source. Replenish the layer every few weeks to maintain its effectiveness.
  6. Once a week, top up the manure in the container to provide a food source. Only remove the mature bloodworms and feed them to your fish, leaving the immature ones to continue growing.
  7. After a week, the eggs will hatch into bloodworms. Rinse them thoroughly before feeding them to your fish to reduce the risk of parasites.
  8. To prevent the bloodworms from turning into midge flies and causing an infestation, control the temperature and light conditions in the container. Keep the container cool and dark, and remove any dead leaves or organic matter that may attract flies.

To maintain a consistent supply of Bloodworm eggs, you can release midge flies and gather their eggs wherever they lay them. Creating a favorable environment, like a shallow and still freshwater pond in your garden, can encourage the flies to lay eggs in a convenient location, ensuring a steady supply.

However, it’s not recommended to let the bloodworms reach the pupal stage and develop into flies. While cultivating bloodworms from eggs as a food source is feasible, breeding midge flies isn’t a practical option for most hobbyists.

Best Practices for Harvesting Bloodworms

When harvesting bloodworms, take precautions to avoid getting bitten or having an allergic reaction. Always wear gloves when handling the larvae.

The bloodworms’ environment can contain parasites and bacteria, which could harm your fish. Thoroughly rinse the harvested bloodworms in dechlorinated water to remove any dirt or water from the container before feeding them to your fish.

It’s not recommended to let the bloodworms mature into the pupal or fly stage. Instead, harvest the larvae once the eggs have hatched. Filter the bloodworms as much as possible to remove mud and manure and store them in the fridge to slow down their life cycle. This can provide you with a food supply for up to three weeks.

If you find flies in the storage bag, it means the life cycle is well underway, and you’ll have to dispose of the whole bag and start over.

Common Problems and Solutions in Bloodworm Cultivation

Bloodworms are the second stage in the life cycle of non-biting midge flies. Cultivating bloodworms indoors is challenging due to the flies breeding in the adult stage, forming dense breeding clouds over freshwater.

To overcome this issue, you can create a habitat for midge flies in your garden, such as an outdoor pond. This will provide suitable conditions for midge fly breeding and a sustainable supply of eggs. To prevent bloodworms from reaching the pupal or adult stage, refrigerate them as bloodworms and feed them to your fish before they advance.

The Risks of Feeding Fish Bloodworms

Here are the risks associated with feeding your fish with bloodworms

  • Bloodworms are a good source of protein and iron for fish, but they do not provide a nutritionally complete diet. They lack certain nutrients and have a minimal range of amino acids, so it’s important to supplement them with other types of food.
  • A diet high in bloodworms can cause digestive issues for fish, including bloating and constipation. It’s important to balance their diet with other types of food to prevent these problems.
  • When introducing live food like bloodworms to your tank, there is a risk that they may carry harmful bacteria and parasites that could make your fish sick. This can disturb the water conditions and in the worst-case scenario, these parasites could even kill your fish.
  • Because bloodworms are so delicious to fish, they may become “hooked” on them and reject other types of food. This can make it difficult to feed them a complete and healthy diet, so it’s important to vary their diet and not rely solely on bloodworms.

How to Minimize Risks When Feeding Your Fish Bloodworms

Feeding your fish a varied and balanced diet is crucial to minimizing the risks of bloodworms. They should be used as a treat or to encourage your fish to eat if they are rejecting other foods.

Only feed your fish bloodworms one to two times a week, and complement them with other frozen food and nutritional pellets to ensure a balanced diet.

Mix of Freeze Dried Bloodworm and Other Varied Diet for Fish

To reduce the risk of introducing parasites and bacteria to your tank, be sure to rinse live bloodworms with dechlorinated water.

Healthy Alternatives to Bloodworms for Feeding Your Fish

If you’re looking for alternative food sources to bloodworms for your fish, there are several options you can consider:

  • Baby Brine Shrimp: These are high in vitamins and amino acids, which bloodworms lack. They are easy to cultivate in captivity and make a readily available food source.
  • Ghost Shrimp: These can make good tankmates for some fish and help reduce algae, but larger fish may consider them food.
  • Daphnia: This is a good live food source, but their rapid breeding can destabilize your aquarium parameters.
  • Infusoria: This is great for feeding Betta fry and other young fish. They are easy to cultivate and live on the plants in your tank.


Bloodworms are a popular food for many fish species. In the wild, fish eat a variety of things to maintain a balanced diet, and it’s important to replicate that in your aquarium.

While bloodworms are a natural part of a fish’s diet in the wild, it’s important to use them sparingly in captivity. Live food poses a risk of introducing parasites to your tank, so you may prefer to use frozen or freeze-dried bloodworms instead.

To promote the health and longevity of your fish, offer bloodworms as part of a varied and balanced diet. Only use them alongside other foods, and avoid overfeeding your fish with bloodworms or any other food source.

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