You might have noticed several linear movements in the fish tank and wondered if it was anything harmful. Well, not to worry, as these may be Detritus Worms.

The worst part is that they do not need your invitation to come and live with the fishes, but the best part is that they are not always dangerous to other living organisms.

These are very common in freshwater aquariums and are not easy to handle, considering their significant number in existence. Hence, it is imperative to understand the culture of the worm.

Here we will tell you all about the Detritus Worms in the aquarium, specifically regarding lifestyle and ways of their removal.

General Profile

Quick Facts
Family Naididae
Common Name Detritus Worms
Water Type Freshwater
Color Off-White
Max. Size 1 Inch
Reproduction Asexual
Breeding Necessities Impurity in Water
Growth Rate High
Feeding Waste Material
Active Hours Nocturnal
Danger Negligible

What are Detritus Worms?

These Worms belong to the Naididae family and exist in almost every water body where aquatic animals reside, whether in closed or open spaces.

There are hundreds of sub-species under the same name, and it is tough to differentiate them according to their particular characteristics.

The Detritus Worms are similar to other parasitic creatures like earthworms, bristle worms, and leeches since they all come from the same phylum, Annelida.

While in the fish tank, you can observe them floating like a white thread in the middle level or over the substrate, such as sand, gravel, etc.

Physical Appearance & Habitat

You must carefully scan the aquarium to verify their presence and ensure specific identification parameters. The worms are either in white or off-white color with thin, cylindrical body structure. These are tiny creatures with an average size of about two centimeters and possess a sectional body with minute spikes or hairs on the skin; hence they are also known as segmented Worms.

They are usually found in the impure region, crawling or wiggling over the water bed. You can only recognize the Detritus Worms through a microscope because it is hard to see them with bare eyes.

Behavior: What do They do in the Tank?

These worms should be termed as nocturnal since they perform most activities in minimal lighting and negligible disturbances in the water.

In the meantime, when other aquatic lives are active during the day hours, they dig small holes in the substrate. After that, it will either stick to the walls or hide inside the sand burrows.

Note: Since they have a sleek body, these Detritus Worms easily penetrate the minute spaces between gravel stones, driftwood, and rocks and rarely witness their existence to the tank owners until their numbers increase.


A notable fact is that leaving out a few exceptions like Ascaris, most of the Worms are hermaphroditic types.

Such creatures possess both the gender-centric organs in one single body and hence have both male and female abilities in one body.

Where do Detritus Worms Come From?

This is nothing unique if such parasites suddenly appear or are noticed in an aquarium.

Their drifting nature can be one of the prominent reasons for reaching unexpectedly into the tank. Additionally, these worms have the ability to attach themselves to plant leaves or fish’s skin, and that is how they traverse to unknown regions.

So, the Detritus Worms might have been introduced while transferring a new fish or plantation to the aquarium when you were unaware of them sticking underneath the fish or leaves of plants.

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These creatures can cleverly hide in the substrate (sand/ gravel), unnoticeable due to their size and color, and enter the new environment when it is added to the tank.

Another factor is a change of tank water, as you may accidentally provide them with an easy entry by filling the tank with unclean water.

Food Habits: How do They Survive?

“Detritus” means debris or junk, and hence the name of these worms rightly signifies their food preferences. As a matter of fact they do not require any specific food items for growth and survival since, they can consume almost anything.

They readily consume leftover food particles or decaying organic matter in the tank. So, in a way, they work hard to remove the waste without any external effort and continuously filter the water.

They are often categorized as natural tank cleaner organisms, which eat slowly but steadily to provide the by-product of sanitization.

Reproduction: How do They Multiply

Once the Detritus Worms reach the aquarium by any means, they tend to look for suitable living spaces while thriving on waste products.

Now they wait for appropriate conditions to reproduce and in due time multiply their family.

These are asexual and do hence, can reproduce without a partner. In short this means a single worm can multiply into an explosion of numbers.

Fact: You cannot kill the Detritus Worms by cutting them into two halves, because both parts will stay alive as two living organisms.

What Instigates Increase in Detritus Worm’s Population

Unlike other aquatic inhabitants, which require hygienic water and nutritious food for sustainability and growth, these worms are entirely different.

They quickly start multiplying in specific situations, and among these, the major causes are overfeeding the pet, and impure water.

It is crucial to induce enough food in the tank, so that the aquatics can eat in 2 – 3 minutes. Undernourishment will deteriorate their health, while over-feeding has other adverse effects altogether.

If you provide food to your fish out of schedule or even when they have consumed sufficiently, it will result in a lot of leftover particles and excessive excretion.

As a result, the water quality declines, and the Detritus Worms becomes active to reproduce successfully.

They eat waste materials, while the poor water conditions suit them immensely to regenerate. The worm keeps increasing in this manner and can stay unnoticed for quite a long time.

Are These Dangerous in any way?

These are minute creatures and are readily available in most fish tank setups, even if the owner is unaware of their existence.

Traditionally, they appear peaceful and harmless to other organisms, but the dangers are completely situational and defined per the perspective of an individual.

Are They Harmful to Fish?

The Detritus Worms do not directly impact fish, crustaceans, turtles, snails, or any other aquatic life.

These are not considered harmful to their tank mates because they are neither disease-prone nor can they bite or injure them.

But they indirectly impact tank habitation when the population of these Worms increases.

A sudden increase in the number will disturb the water parameters by reducing oxygen level and increasing nitrogen, thereby troubling the aqua life.

Are They Harmful to Humans?

The Detritus Worms are not at all harmful to human beings. They can only survive in water and die if somehow filtered out of the tank.

When you pour your hands into the water, these worms can cling to it but cannot penetrate the skin, or suck-in blood like leeches, as they are not poisonous. After finishing the tank work, one should thoroughly wash their hands to stay protected from bacteria or tiny parasites.

How to Get Rid of Them

The Detritus Worms are organisms that grow rapidly under favorable conditions, as discussed above, and most likely, you may not know about their existence for a long time.

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And now that you have located their presence in the tank, it becomes a choice to work on getting rid of them or let them stay.

Many tank owners feel that since they are not harmful to the aquarium inhabitants and, on the contrary, help in the cleansing process, it is worth not making efforts for their removal.

But as the population of Detritus Worms increases, they seem hazardous to the local environment and should be pulled out.

It is slightly tricky to filter them out of the water. Here are some measures that you can take to manage the excess population of these worms.

  • Refresh the Tank Water: However, this is not an efficient solution you may apply it as an instant option. But you require sufficient space to comfortably transfer all the plants and animals and avoid any misfortune.

The replacement should not be more than one-third of the water since a total change will severely affect the life of aquatics.

So, the process is helpful in partially reducing the population of worms, but repeating the steps every week can make a huge difference in controlling their growth.

  • Use of Chemicals: You can use chemicals like Hydrogen Peroxide to purify the water and eliminate Bacterial impurities.

Other popular chemicals or medications that can work are Fenbendazole, Prazipro, etc.

But before applying this technique, you should consult a local veterinarian about its harmful effects on your specific aquarium habitants apart from these Worms.

The dead Detritus Worms will lay on the floor and decompose over time to release ammonia, which is unsuitable for fish. Hence, these should only be used in a controlled amount.

By and large, such purifying ingredients do not impose any adverse effects on the aquatic animals or plants. These are primarily used to treat parasites, worms, algae, larvae, eggs, or even execute unwanted snails.

  • Get Gravel Vacuum: It is a piece of mechanized equipment used to catch the waste products like food particles or fish excrete lurking at the bottom of the tank.

Anything left out for long in the water will reduce the water quality, making it favorable for the growth of such worms.

Use this tool regularly to clean the tank’s substrate, walls, and other accessories and ultimately control the growth of such uninvited guests, even if you haven’t noticed them yet.

Note: The aquarists often get to see the Detritus Worms trapped inside the gravel vacuum after tank cleaning.

  • Check the Tank Filter: The fish keepers usually install water filter machines to continuously clean the water, which helps maintain the hygiene and oxygen level for the healthy petting of fish.

But avoiding the filter maintenance practices can make the whole process worthless. These filters often require cleaning as they acquire waste material and, if not removed, can eventually circulate the same impurities in the tank.

It is easy to clean the Detritus Worms stuck in HOB filters, as they are simple and portable, and regular cleansing will let you know the approximate population of these worms in the tank.

  • Feeding Schedules and Choices: The Detritus Worm’s growth highly depends on what you provide and how you feed your fish in the tank.

While overfeeding is one of the biggest causes of them, providing live food may also bring in more of these worms to the tank, who are habitual of traveling long distances by sticking to the animal’s skin.

The unconsumed food particles or waste produced due to overfeeding will stay in the gravel and sands at the bottom if not removed. These decaying plants, flesh, or pellets & flakes increase the growth of such Parasitic creatures.

Thus, you should adequately schedule the feeding scenarios and try to remove the leftover particles.

  • Tank Maintenance: You must regularly maintain the tank parameters, hygiene levels, and co-existence of aquatics.
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The higher the number of fish in the tank, the more the waste material will accumulate, which continuously alters water conditions and paves the way for these Detritus Worms. Many aquatics go through molting processes, and the skin sheds away in the tank, leading to decomposition if not removed.

Therefore, it is imperative to not over-crowd the place and keep noticing the parameters and cleanliness levels in the tank.

  • Removal Through Consumption: Many aquatic animals deliberately eat these Detritus Worms. So, it can be a soothing formula to pet some of them in the aquarium.

There are many fishes and other animals that can happily feed on the worms, but you first need to find out if the worm eaters are compatible with other tank mates or not. The big aquatics usually avoid these tiny awards, so baby fish are the right option.

What Eats Detritus Worms

It is almost impossible to have an aquarium without Detritus Worms, even if they are in small numbers.

But if you haven’t spotted any of these in your fish tank, the most prominent reason could be the presence of aquatic animals that are regularly consuming them.

It has been observed that many aquatics like amphibians, and fishes, especially if they are small-sized or at the juvenile stage, will eat worms. On the contrary, larger ones usually show disinterest towards them.

The sucker-mouth types find them easy to gulp while swimming, but the Detritus Worms become the most suitable food option for scavengers, since they mainly crawl over the substrate.

All the loaches (fish varieties) like Clown, Kuhli, Zebra, etc,. prefer these worms in their diets and specifically search for them in the aquarium.

Corydoras Catfish, Bettas, Plecos, etc., are other fish that occasionally eat Detritus Worms, but you must also provide other supplements.

Note: Some experts also claim to register the Shrimps eating Detritus Worms, especially Amano Shrimps, but this is only rare, and they generally avoid Worms.

What are Planaria Worms and How are They Different From Detritus Worms

Planaria Worms, like the Detritus, are also living organisms of the water World, but they have many different characteristics.

These worms are not very common due to the lower reproductive rate, but with their noticeable features, one can identify them crawling on the glass walls of the tank.

They possess a pointed head while the mouth is located in the middle part of the underside body. There are eye spots or photoreceptors present throughout their bodies, although it depends on the subspecies classification, as few may only have two such spots over the head.

If you cut these worms vertically or horizontally, they will become two or more new living Planarians.

Let us find out more about these Worms in a comparative analysis chart.

Planaria Vs. Detritus Worms

Here are a few interesting facts about them.

S.No. Parameter Detritus Worms Planaria Worms
1 Phylum Annelida Platyhelminthes
2 Shape Round (Like Thread) Flat (Like Ribbon)
3 Structure Thin Thick
4 Color White Black, Brown, Blue, Gray, White
5 Size 2.5 cm 4 cm
6 Danger Harmless Harmful
7 Diet Debris Carnivores
8 Movement Swim & Crawl Glide along the surface
9 Reproduction Type Asexual Both (Sexual & Asexual)
10 Growth Rate High Slow
11 Habitat Freshwater Saltwater and Freshwater

Frequently Asked Questions

Are Detritus Worms bad?

No, these worms are not always bad, as in the long run they ultimately clean the tanks. It happens as a result of their living standards and feeding style which are pretty helpful in maintaining the aquarium’s environment.

Do Snails eat them

Snails do not eat Detritus Worms, although they are pretty popular as tank cleaners since they consume all the leftover and waste materials that cause the growth of worms.

Are Detritus Worms the same as Micro Worms?

The Micro Worms are entirely different species and belong to the Phylum Nematodes, while the Detritus is an Annelida. As the name suggests, the Micro Worms are minute organisms that grows up to 0.5 – 1.5 mm, and henceforth, are considered healthier food for fish fry after the infusoria stage.

Vinegar Eels and Walter Worms are non-Parasitic creatures and are recognized as Micro Worms.

Can they live outside of water?

These creatures are typical aquatic inhabitants and will purish if removed from the water. But considering their size, it is hard to pick them up or separate them out of water.

Final Words

The Detritus Worms are an unsolicited guests to the aquariums, and at the same time unstoppable at any cost. Eventually,  their regulated presence in the tank does not creates any direct concern to the species, but you must not let them multiply uncontrollably.

So, it does not matter if you haven’t noticed their presence; you must follow the strict guidelines of tank hygiene and other procedures to not let them disrupt the local environment.

About the Author

Shelby Crosby

Shelby is a passionate fishkeeper who has been writing about fish for over 5 years. She is a pro aquarist and holds a BSc Honors Degree in Wildlife and Fisheries. She creates her own beautiful aquarium layouts and loves to share her knowledge of tropical fish with other hobbyists. Career Highlights: Has worked with several…

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