Bloodworms: All You Need To Know About This Aquarium Food

Bloodworms can refer to a few different types of worm including the two most popular ones; the small red larvae from midge flies (Chironomidae) and the genus Glycera a group of worms that are usually found in marine waters.

Both of these worms are suitable for feeding fish.

Most of the worms that you find for sale are the small red larvae variety, and are not actually worms.

You can buy bloodworms either live, frozen or freeze dried. We’re going to take a look at the benefits for each of these, which species of fish will eat them, and how to feed them along with some recommendations of which ones are best for your fish.

All About Bloodworms

Red Larvae of the Midge Fly
Bloodworms, the larvae of the non-biting midge fly, are bright red in color. They have this color due to the red iron-porphyrin protein in their blood and tissue. They can thrive in polluted water with low oxygen levels because of their hemoglobin content.

This creature is one of the primary foods in the aquatic food chain. Almost every species of meat eating fish will consume this worm. It is also used to feed other aquatic animals such as salamanders, turtles, crabs, frogs, shrimp and snails.

Worms from the genus Glycera are a group of bristle worms that are usually found living on the seabed of marine waters. They can grow up to 14 inches and are a creamy pink color. They also have a venomous bite.

Types of Bloodworms

Freeze Dried Bloodworms

Omega One Freeze Dried Blood Worms
Omega One Freeze Dried Bloodworms

If you’re looking for a small tub, this 0.46oz container of freeze dried blood worms is ideal. Omega One offer one of the best quality options around.

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Freeze dried ones usually come in small plastic tubs.

You will find that some freeze dried come in Grade A and Grade B. Although Grade A is slightly more expensive, it’s worth paying the extra because Grade B are lower quality and can contain non bloodworm particles.

Despite them being the least nutritional, they are the most convenient way to feed your fish.

To feed this food to your fish, soak it for a couple of minutes in water before adding it to the tank. This will soften it.

Freeze dried varieties usually float at the top of the tank, so if you want to feed them to bottom dwellers, soak them for around 10 minutes before adding them to the tank.

San Francisco Bay Freeze Dried Bloodworms
San Francisco Bay Freeze Dried Bloodworms

If you’re looking for a larger container of freeze dried bloodworms, then this 1.75oz tub is great. It has over 50% crude protein, and makes a great treat for your fish.

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Live Bloodworms

Live bloodworms aren’t always as easy to find as frozen ones.

They also don’t keep as long as the frozen or freeze dried varieties. The larvae life cycle is short, usually just 10-12 days, and they should be used within 2 or 3 days of buying them.

Live worms usually come in a plastic container. You should rinse the worms before feeding them to the fish and don’t add any of the water in which they were stored to your tank.

You should store them in the fridge, with enough water to cover the bottom of the container.

They are ideal for large tanks which have many fish.

Whilst live foods are usually more nutritious than frozen foods, they do have a higher risk of carrying infection and disease. For this reason, it’s not recommended to collect your own worms or larvae from the wild.

One way to avoid contaminating your tank is to buy your live foods from a reputable breeder.

Live ones are ideal for conditioning fish if you want them to breed; they are commonly used to condition Betta fish.

Feeding them live foods will also bring out the hunting instincts of your fish and you will see more of their natural behaviors.

Frozen Bloodworms

Frozen ones are more convenient than feeding live foods as they keep for much longer (up to 6 months) in the freezer.

They come in a few different forms, from frozen blocks to thin sheets.

One of the benefits of using frozen worms is that it’s unlikely they will be carrying any parasites or disease.

To only downside of feeding them frozen worms is you will miss out on watching your fishes’ natural hunting behaviors.

When you are ready to feed your fish, fill a small container with some of the tank water and place a cube of bloodworms in, to thaw it out. Once it has thawed, strain the defrosted food to remove the water and excess juices.

Whilst many people add it all to the aquarium, it can be an unnecessary bio-load on the filter as the fish won’t eat the juices.

If you only have a small tank, you’ll want to cut the cube in half to ensure you don’t over feed the fish. You can judge this by watching them when you add the first few cubes. Time them for a couple of minutes and if there are any leftover worms after this, you’ve overfed them.

Use the first few times to determine how much you should be feeding your fish. It’s better to add less at first and increase the amount you’re feeding them over time.

When you add them to the tank, you can either do a mass feeding and add the whole lot over the length of the tank, or you can feed fish directly. To do this you can use either pipette or tongs.

Which Fish Can You Feed Bloodworms To?

All freshwater and saltwater fish that are either carnivorous, or omnivorous.

Bloodworms are known as the ultimate bait fish, because 99% of fish will eat them.

They can provide your fish with lots of protein, but it is important not to over feed them. They should not be used as a complete diet, rather as a supplement to their regular diet which is usually flake or pellet food.

Even though they are rich in iron and protein, they lack other essential amino acids, minerals and vitamins which your fish need to breed, so always feed them alongside their staple diet.

Bloodworms are also used to condition fish that are about to breed.

They are usually high in protein so are better suited to fish such as Bettas, and any livebearer such as Mollies and Guppies. This is a popular food for Discus, Eels and Loaches too.

Breeding Your Own Bloodworms

You might think breeding bloodworms would be cheaper and more convenient than buying live ones.

Breeding your own means you known the conditions they have been bred in and you can minimize the risks of parasites and disease. However, breeding them is difficult and not practical for most hobbyists.

Unlike breeding fish, bloodworms can be tricky to breed because you need to have somewhere that they can fully mature into flies – the flies are prone to flying away to lay their eggs elsewhere.

There are four main stages of their life cycle; egg, larva, pupa and the adult midge. The main difficulty lies in the inability to be able to induce swarming and mating of midges in captivity.

Most hobbyists who breed their own use either tubifex worms or blackworms.

Omega One Freeze Dried Blood Worms
Omega One Freeze Dried Bloodworms

If you’re looking for a small tub, this 0.46oz container of freeze dried blood worms is ideal. Omega One offer one of the best quality options around.

Get Bloodworms Now

Frequently Asked Questions about Bloodworms

Do Bloodworms Bite?

Most species in the Glycera genus will bite. The Gylcera fallax was studied by a group of scientists and found to have a bite which causes a similar allergic reaction to bee strings.

Are Bloodworms Dangerous To Humans?

The only real danger from bloodworms is being bitten, so you might want to wear gloves if you’re handling live ones.

How Often Should You Feed Your Fish Bloodworms?

You can feed your fish live worms once or twice a week. Remember though, you should always feed your fish a varied diet. Over feeding your fish with bloodworms can lead to constipation.


If you are reading this, the likelihood is you’re trying to figure out whether you can feed your fish bloodworms. Providing they are either omnivores or carnivores, the answer is yes!

Just be careful that you don’t over feed them, and that you provide them with a varied diet.

Go ahead and try introducing this delicacy to your fish – they will definitely thank you for this tasty treat.

What fish do you have, and do they enjoy bloodworms? Let us know in the comments below…

About Robert 247 Articles
Robert Woods is the creator of FishKeeping World, a third generation fish keeper and a graduate in animal welfare and behavior. He is also a proud member of the Association of Zoos and Aquariums, the Marine Aquarium Societies of North America and the Nature Conservancy.


  1. Thanks for your weekly advice it’s been really helpful it answers a lot of questions and give me lots of ideas thanks . The question I have is Is it safe to feed my African cichlids live Redwigglers once/ twice a week after being cleaned in water from aquarium again thanks

  2. I’ve tried feeding my fish bloodworms but they always sink almost instantly, whether I defrost a small amount or put half a frozen block in (as recommended by my local fish store). Does anyone have any recommendations on how to get them to float long enough so my fish can eat them?

  3. I have Datnoids.. The three larger ones (4inches) eat pellets and frozen bloodworms, The other 4 (3 inches)will only eat the bloodworms. I have a 135 gal tank. Should I starve the smaller ones and only feed the pellets with occasional worms or just feed the big ones pellets and hope the little ones start eating them. The shrim pellets Are small enough for them all but the small Dats ignore them.

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