Are Bloodworms Harmful To Dogs?

Many pet lovers care for a variety of species, including dogs, cats, fish, and reptiles. Keeping a variety of pets with vastly different nutritional needs can raise some out-of-the-ordinary questions, such as what are bloodworms anyway, and are they dangerous? Do bloodworms cause allergic reactions? Are bloodworms harmful to dogs? 

Knowing the answers to these questions probably won’t matter much if you aren’t an aquarist or a person who lives in an area where midge flies are a problem. However, if you are, you need to know that bloodworms are typically harmless and aren’t likely to hurt your dog. However, they can cause problems for you and/or your dog if you or she are asthmatic or allergy-prone.

What Are Bloodworms, And Are They Dangerous?

Before we get too deep into this topic, it is important for you to know the difference between larval bloodworms and tubifex bloodworms. 

● Larval bloodworms are midge flies in their larval state. They are frequently used for tropical fish feeding, and these are the bloodworms about which this article is written. 

● Tubifex bloodworms, also known as red wigglers, are in the earthworm family and are used for fishing bait. 

●       Tubifex bloodworms are not harmful to dogs. Larval bloodworms typically are not, but they may cause allergic reactions in sensitive, allergy-prone dogs and humans.

Bloodworms And Allergies.

Larval bloodworms are not parasitic and are typically considered harmless. However, a growing body of evidence suggests that bloodworms cause serious allergic reactions in people exposed to them. While no cases of severe anaphylaxis have been reported in dogs, it is wise to pay attention to your dog’s behavior after ingesting bloodworms. If they show signs of an allergic reaction, take her to her vet or seek emergency veterinarian services if the reaction is severe.

What are the signs of a bloodworm allergy in dogs?

Any allergic reactions in dogs can be as mild as itching or as serious as anaphylaxis. Many symptoms are between these extremes. If your dog sneaks a snack of bloodworms, watch out for the following, and seek appropriate medical care should a reaction occur.

● Itching and scratching.

● Chewing.

● Sneezing.

● Coughing.

● Running, watery nose.

● Watery eyes, or red eyes.

● Rubbing her face and body against the floor, walls, or furniture.

● Whimpering.

● Shortness of breath.

● Asthma attack.

● Anaphylaxis.

As with any strange food, bloodworms may cause diarrhea and a rumbly tummy, but these are most likely to be from eating something she is unfamiliar with, not an allergic reaction.

Are Freeze-Dried Bloodworms Bad For My Dog?

Many people who own tropical aquariums supplement fish food by feeding live or flash-frozen larval bloodworms. These worms are high in protein and nutrients many fish foods lack. However, many mistakenly believe that if the live or frozen bloodworms cause an allergic reaction, freeze-dried bloodworms are a better choice. 

While it’s true that freeze-dried bloodworms are easier to handle than the live or flash-frozen varieties, it is not true that they are better for those with bloodworm allergies. In fact, they are much worse.

Freeze-dried and fragile.

Processing freeze-dried foods remove moisture from the product without disrupting the general nutriment. While this makes for easier handling, it does cause fragility in bloodworms. At packing, some breakage is unavoidable, and during shipping and distribution, more breakage occurs. This breakage releases bloodworm particulates to circulate within the bag or container. Once opened, these particles become airborne and can be inhaled by humans and dogs.

Some evidence suggests that bloodworm allergies increase in severity with repeated exposure. What this means is that even people or animals who have never had allergic symptoms can develop them over time.

How Do I Keep My Dog From Eating Blood Worms?

The easy answer to this is to keep them out of your dog’s reach. Keep frozen bloodworms in the freezer, and return the package to the freezer immediately after feeding. If you use live bloodworms, store them out of reach of your dog according to the package instructions. If you use freeze-dried bloodworms, keep the bag or container tightly sealed and in a place your dog can’t go. 

If your dog shows any signs of allergies to bloodworms, put your dog outside or in a separate room at feeding time. 

 Controlling outdoor exposure.

Perhaps you are not an aquarist, but rather, you live in a midge-prone area of the world. Since midges rely on water for reproduction, bloodworms are usually found in stagnant water. How do you keep your dog from snacking on midge larvae they finds outside? Here are some ways you can make your yard or garden less attractive to midges.

● Empty, clean, and refill water bowls, troughs, or bird baths each day.

● Eliminate dips and pits that collect water.

● Clean up debris that holds water, such as old tires, kiddy pools, rotting stumps, etc.

● Keep your gutters clean.

● Flush and treat drainage ditches regularly.

Denying midges access to standing water will reduce your dog’s exposure to their larvae. It will also have the added benefit of reducing the nuisance of mosquitoes and their larvae, which can absolutely make your dog sick!

Bloodworm Alternatives.

If you’ve decided that you’d rather not take chances with bloodworms, what can you feed your fish instead? Here are some suggestions that are safe for you and your dog.

● Frozen beef heart treats.

● Frozen plankton.

● Spirulina brine.

Consult your aquatic store for more alternatives.


Bloodworms are certainly a carnivorous fish favorite, and with proper care and handling, they are safe for aquarium use. However, they do have the potential for serious allergic reactions in people and possibly in pets. 

Suppose you recognize symptoms of bloodworm allergies in yourself. In that case, you should certainly discontinue feeding bloodworms to your fish and get appropriate medical attention. It is wise not to feed your dog bloodworms nor allow her access to them. If she gets into them, watch her for signs of allergic reaction. And remember that just because there is no reaction this time doesn’t mean there won’t be one next time. 


  • Brad

    Hi I'm Brad, the founder of Having been a vet of 6 years I work alongside our team to provide valuable insight into your dog's health. I have a frenchie myself named Senzu who is my pride and joy!

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