Can Earthworm Live in Aquarium? All You need to Know

If you have had snails or shrimps in your aquarium, you might be curious whether adding earthworms to your tank is a good idea or not.

Earthworms are known for being beneficial in gardening for many plants so, maybe they could be good for your planted tank, right?

Both snails and shrimps are good additions, especially in planted tanks, since they eat up much of the fish waste and control algae.

However, before you start considering the benefits of earthworms, it is a good idea to consider one major question – can earthworms live in an aquarium?

Let’s try to find the answer to this question here.

Can Earthworm Live in an Aquarium?

Yes…. but No. Earthworms are hardy and are known to survive in harsh conditions. If you place them in a tank, they can survive. But you really should NOT keep them in your aquariums. On the surface, this idea can seem like one that has some merit behind it, but it isn’t a good idea.

Earthworms breathe through their skin and they live in moist environments.

Most are usually found in the clay banks and soil around lakes too. So adding them to your tank should work, right?

While it is a wonderful idea in theory but honestly, earthworms aren’t meant to live underwater.

Hazards of Keeping Earthworms in Your Aquarium

Keeping earthworms in aquariums isn’t suggested because it can be an additional hassle. Plus, you have the following hazards to consider:

Not Enough Substrate

Few tanks offer enough substrate and soil for earthworms to burrow and live in.

Earthworms do not like light or being out in the open water. A thick, soil-based substrate is a must for them to thrive.

This also means that in non-planted tanks, earthworms will not be able to survive because soil substrate is largely reserved for use in planted tanks only.

Also read: How to Change Aquarium Substrate

High Oxygen Levels

The water needs to be properly oxygenated in order for the worms to get enough oxygen.

This can mean that with earthworms, you will have to keep high oxygen levels in your water tank.

It might seem like it is good for everyone but, it can be difficult to maintain. It should be noted that not all fish and plant life will thrive in high oxygen.

Also read: Can Fish Live Without Oxygen Pump?

Can Mess Up the Tank Chemistry

With high oxygen and active fish, you might assume that your fish are happy because some can become very active.

However, they will also produce more waste materials such as carbon and nitrogen.

This could throw off the natural chemistry of your tank and you will have to monitor the parameters constantly to make sure that your fish don’t suffer because of it.

Contribute to Waste

If you were hoping that the worms will help with processing the fish waste, you might have forgotten one crucial detail – earthworms also make waste.

Worm castings can be beneficial for fertilizing the soil in gardens but in an aquarium, they could also contribute to making the substrate dirty very quickly.

These are some of the major hazards that you have to consider when you want to add earthworms into your fish tank.

Have People Kept Earthworms in Aquariums?

Most people have not bothered to add earthworms in their planted aquariums because of the reasons discussed above.

The cases you will commonly read about online are when people were using earthworms to feed their fishes and one or two managed to escape into the substrate.

Even then, these people didn’t pay attention to the worms.

It was only when they were cleaning the substrate by vacuuming it that they found these worms.

Again, these worms survived only by chance and even then, weren’t observed until the substrate was disturbed.

No aquarium keepers have tried to actively keep earthworms in their aquariums. If you do try this, you have to be careful.

Plus, if you have fish that you feed on earthworms, the fish might hunt and eat these worms when they see them.

So, good luck in trying to add these worms to your planted aquarium!

There Are Worms in My Aquarium – Are They Earthworms?

Have you seen worms in your aquarium? In most cases, these are not earthworms.

These are known as aquatic worms and they are not good for your plants or for your fish.

In fact, certain types of worms can actually be harmful to the fish in your tank. These aquatic worms can be a natural, normal occurrence for your tank.

However, most times, they are an indicator that something is not right in the tank.

Worms can come into the tank when you add new fish or plants. In fact, it is impossible to keep your tanks 100% free of worms.

In such instances, you will want to make sure that you identify them properly and apply the correct preventative measures.

If you are not sure about the worms in your water, take a small container and scoop them up in it.

Now, take the water and worms to an experienced aquarium owner.

They will be able to identify what kind of worms you have in the water and guide you about the proper treatment.

Identifying the Aquatic Worms in Your Aquarium

Identifying the worms in your aquarium is important because aquatic worms tend to be parasitic in nature.

They can either be external or internal parasites that cause a lot of harm to your fish.

Unfortunately, certain types of aquatic worms are invisible to the naked eye but you can look at the behavior of the fish to learn more.

The following are the different kinds of worms you can find in an aquarium:


These small worms are known to cause extreme irritation to the fish. They can affect the gills, the eyes, and the skin of the fish.

Flukes are naturally present in the mucus layer of the fish’s skin.

While they are normally in a dormant state, any stress or illness will cause them to grow and multiply unmanageably.

In such cases, the fish will start to show signs of distress and illness.

Most common signs to look out for include flashing of fins, irritated skin, rubbing on tank objects or walls, and signs of bruising caused by excessive flashing.

Luckily, you can easily treat these parasites. However, eradicating them is not an easy process.

Additionally, fishes can also transfer the flukes to other inhabitants, especially if they are in a community tank.

To prevent infections, always quarantine the new fishes you get for a minimum of 3 to 4 weeks.

This gives you sufficient time to monitor their behavior, identify any signs of flukes, and treat them properly.

Anchor Worms

These are other forms of aquatic worms that you will commonly encounter.

They are parasitic in nature and tend to burrow deep into the muscle of any fish.

The first sign of these worms will be visible in the form of large ulcers on the body of the fish.

Anchor worms can be very irritating for fish and tend to contribute to weakening their immune system.

This leads to the development of secondary infections. Luckily, treatment can be done easily of anchor fishes.

Most aquatic vets will sedate the fish and manually remove all the worms.

Similarly, the tank will also get treated to eradicate all the worms and their offspring.

Be careful to look for obvious signs because if left untreated, your fish could succumb to the ulcers it causes.

One fish can also infect others so if you have a community tank, quarantine the one which is showing obvious signs of having anchor worms.

Its treatment can be carried on in the other tank without harming the plants and natural bacteria in the main tank.

Bristleworms and Fireworms

Both worm types are largely found in saltwater tanks. They are very distinctive because they sting intensely if you touch them with your hand.

Their bristles have a powerful neurotoxin which causes irritation and a burning sensation on the site.

Fire worms are related to bristle worms and have an even more powerful sting. Luckily, these do not harm fish but they are still unpleasant to have in the tank.

It is a good idea to avoid touching them, especially without gloves because of their powerful stings.

The most effective method to deal with fireworms and bristle worms is to stop leaving a food source for them.

This means that you should only feed your fish as much as needed. Overfeeding will leave extra fish food which will sink to the ground.

Without enough food, these should die out naturally. Interestingly, bristle worms and fireworms are related to earthworms.


These are internal parasites and can be pretty hard to identify. It can be difficult to see the passing of segments of these worms in the waste of the fish.

However, there are some common signs such as loss of weight and inability to thrive.

If all other factors such as pH level of the water, diet and water temperature are all ruled out, your fish may have tapeworms.

Even then you will have to make sure to have a stool sample to examine under a microscope to properly gauge their presence.

Once their presence has been identified, make sure to isolate and put the fish in quarantine. You will also have to give them medication through their food.

Water treatments aren’t the best when you want to treat internal parasites. Food medication can be found at any vet for your fish.

With the help of this medication, you can easily ensure that your fish is in healthy shape and doesn’t infect others when it starts releasing the worms in its waste.

Hookworms or Roundworms

These two types of worms are internal parasites but you need to be careful in handling them because they can infect people as well.

Other invertebrates such as shrimp can also carry hookworm or roundworm nematodes.

This can also cause larval migrans, a disease that happens when the larva of the hookworm starts to migrate.

They will move from the intestine and into the tissue and infect the entire body. This infection can happen to fish and even humans.

To avoid this from happening, be vigilant. One major downside is that identifying signs of hookworms and roundworms can be difficult.

You should apply the same parameters that you did with the tapeworm treatment.

Make sure to wear gloves when handling your fish and checking for worms. Remember to use food medications as they are found to be the most effective.

If you see any sign of the worms mentioned here, make sure to quarantine your fish and treat them as quickly as possible to prevent any fish deaths.

As you can see, aquatic worms aren’t the best to have in your aquarium.

Guidelines for Keeping Earthworms in Your Aquarium

If you insist on keeping earthworms in your aquarium, just know that this is definitely uncharted territory in this hobby.

Most hobbyists are more than happy to keep their tanks free of worms.

Nonetheless, if you are fixed upon adding them to your tank, the following is what you should consider:

Have a Soil Substrate

Always have a thick soil substrate for the earthworms.

They will want enough room to burrow and move around in without getting exposed. Sand or gravel isn’t ideal for them.

Keep High Oxygen Levels

Oxygen levels will need to be kept high as earthworms breathe through their skin.

The water will have to be oxygenated to allow them to get all the oxygen from it.

Monitor All Parameters

Make sure to constantly monitor all the parameters of your tank, especially the pH, nitrates, and ammonia levels of the tank.

With high oxygen, these parameters can become disturbed and your plants and fish might suffer because of it.

Given the high maintenance and attention that adding earthworms to an aquarium will demand, it is a good idea to avoid doing this with your first tank.

It’s best to try this when you understand how to look after a tank and can be comfortable in tweaking the parameters without experiencing any losses.

You may also like the following articles about fishkeeping and aquariums: