Detritus Worms 101: Effects, Causes, and Prevention

Dr. Mollie Newton
Published by Dr. Mollie Newton PHD| Senior Editor
Last updated: July 11, 2024
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If you’ve ever seen thin, white, hair-like objects squirming in your tank, it might indicate the presence of detritus worms. While this isn’t necessarily a good sign as it could suggest overfeeding, there’s no need to panic because a solution is available. Keep reading to learn more about detritus worms and ways to prevent them from taking over your tank.

Article Summary

  • Detritus worms are aquatic pests that can infest aquariums, particularly when there are poor filtration, unclean water, and poor water quality.
  • They can enter aquariums through fish, plants, or substrate, emphasizing the importance of quarantining new tank additions.
  • Getting rid of detritus worms is best achieved through preventative care, including regular tank cleaning, water changes, and avoiding overfeeding.

What are detritus worms?

Naididae Swimming
Naididae Swimming(1)

Detritus worms are an aquatic pest that most fish keepers don’t even realize they have. They are in the same family as earthworms (phylum annelida) and generally do not cause a problem in clean aquariums. On the other hand, once there’s poor filtration, unclean water, and poor water quality you can have an infestation.

What do detritus worms look like?

Detritus worms are annelid worms which means they are segmented worms, much like their soil-based relatives, the earthworms. They are generally long, thin, and whitish-brown in look.

Do all tanks have detritus worms?

If you have added a new fish or new plants to your tank recently you might have accidentally added this aquarium pest. However, you will likely not notice them until there is a severe infestation as they reproduce rapidly and can overtake your tank in a matter of days. Once you begin to notice the population of detritus worms you can go ahead and assume your tank needs a thorough cleaning.

What causes detritus worms

Detritus worms exclusively feed on excess waste from plants and animals. When excess food becomes available from declining tank conditions the detritus worms will begin to multiply taking advantage of the large food source. Generally, the detritus worm population will remain in the substrate until their population has grown so large that they are forced into the water column where it will begin swimming freely.

How detritus worms get into aquariums

Detritus worms are microscopic and can enter your aquarium without you even noticing, this is one of the reasons it’s so important to quarantine any new tank additions for at least 2 weeks before you add them to an aquarium. The three most common ways for detritus worms to enter an aquarium are through transfers of;

  • Fish
  • Plants
  • Substrate

Many tank owners assume that they don’t have to quarantine a species if it is coming from another tank in their home, but you should regardless because two tanks can have completely different microbial environments.

What do detritus worms do?

Detritus worms will eat the fish waste and other decaying organic matter in your tank, and a small population of them won’t hurt your aquarium fish or tank inhabitants. In fact, they will help break down dead plant matter or plant waste, and uneaten food, and will help keep your aquarium clean.

Are detritus worms bad for your tank?

Unlike most worms, detritus worms are actually not bad for your tank, but a large population of them could mean something is severely wrong with your water parameters. The problem with your tank water might not be what you expect, as most of the time large amounts of uneaten fish food and animal waste cause high ammonia and nitrate levels.

However, a detritus worm problem could mean you have low dissolved oxygen (likely because of the increase of aquatic animals-worms are animals too!) or abnormal pH levels.


Another way to manage high ammonia and nitrate levels is to use biopellets.

What’s the difference between planaria worms and detritus worms?

Unlike detritus worms, planaria worms have eye spots and antennae, they are also not segmented and tend to be shorter and flatter. They are often found on the sides of your aquarium along the glass whereas most detritus worms are found in the substrate. Planaria worms won’t bother other fish, however, they will feast on fish eggs given the chance.

Are detritus worms harmful to fish?

No, unlike phylum nematodes which have many parasitic worms that are harmful to fish, detritus worms do not threaten healthy fish.


It is often thought that detritus worms are the cause of sick fish. However, the worms are a result of unclean tank conditions which can lead to sickness and eventually dead fish.

Are detritus worms harmful to humans?

No, these worms will not harm you or any tank inhabitants and only eat dead plant matter and animal waste. However, you might see them catch a ride on fish or other tank members.

Should you get rid of detritus worms?

If you see detritus worms floating around your fish tank you should probably go ahead and get rid of them. The reason is that they can very quickly take over the tank, depleting oxygen levels and crashing your system.

How To Get Rid Of Detritus Worms

Your first thought to get rid of these worms might be chemical treatments or medication. However, chemicals and medicine don’t work on detritus worms, but they can be harmful to many aquatic animals in your tank. The most effective way to get rid of these worms is through preventative care (such as cleaning your tank regularly) and consistent water changes.

Aquarium Water Change
Aquarium Water Change

Water Changes

The first step in addressing an infestation is cleaning the fish tank and doing a water change. While you should already be cleaning your tank regularly, we mean a heavy and proper cleaning of the tank. Some common areas of waste buildup include:

  • Aquarium glass
  • Behind your filter
  • Substrate
  • Decor
  • Plants

I suggest using brushes or scrapers to clean algae from the sides of your tank and decorations, and a gravel vacuum to clean the substrate thoroughly.


Don’t use any cleaning materials that might have come into contact with soap or other household chemicals as they are harmful to all fish species.

Try to clean as much of the substrate as possible without harming any plants or bottom feeders in your tank. Since this is where the worms spend most of their time you’ll likely see a large amount of them get sucked up into your vacuum.

Any tank decorations or artificial plants should be removed and either soaked in an all natural aquarium safe sanitizing solution or in a bleach solution (1 part bleach:19 part water) for 15 minutes. Then rinse using spring water and leave it outside of the tank until you have finished disinfecting the aquarium.

To rid live plants of any harmful bacteria you can dip them in a hydrogen peroxide solution. Use 2-3mL of 3% hydrogen peroxide per 1 gallon of water and allow plant leaves (NOT THE ROOTS) to soak for 3 minutes. This won’t work for plants that are rooted in your substrate but is beneficial for floating plants.

Filtration System

Your filtering system can harbor a lot of bacteria, both beneficial and harmful. The trick is to use cleaning methods that won’t destroy the good bacteria. Depending on what sort of filter (canister filter, under-gravel or substrate filter, backpack filter) you have you can detach it from the tank completely and rinse it in the sink, or you may need to flush or backwash the system. Either way, you should thoroughly rinse the filter, then remove the media and rinse with conditioned tap or spring water.


You should be regularly checking your filter to make sure that it is working. A filter that breaks overnight can cause very rapidly degrading conditions depending on the tank’s bioload and size.

Avoid overfeeding

Avoiding over feeding falls in the preventive care section of how to prevent a buildup of detritus worms. To avoid feeding your fish too much you should observe their feeding habits, and if there is any leftover fish food at the bottom of the tank or in the water column. Leftover food could be the result of several problems such as;

  • Small fish-you are feeding your fish too much for their size
  • Shrimp tank-many invertebrate tanks tend to be dirty by nature of keeping invertebrates
  • Betta fish and other picky eaters- if you have a picky eater chances are that some food will drop to the bottom of the tank


If you have gravel or river stones as substrate it makes it hard to see and retrieve uneaten food. On the other hand having sand as substrate can cause hidden ammonia pockets if leftover food is left in your fish tank.

Do fish eat detritus worms?

Most carnivorous fish in your tank will eat detritus worms if they come across them, but will not actively seek them out. Because these worms are present in many aquariums regardless of water parameters you can assure yourself that at some point in time your fish has eaten them. In fact, in their natural environment, most fish are likely eating detritus worms as supplemental nutrition.

Fish Eating Detritus Worm

How to prevent detritus worms

Regardless of how they got there, you should avoid creating optimal conditions for detritus worms in your fish tank setups. It is easier to prevent worms than get rid of them. Prevention methods can include quarantining new additions to your tank and avoiding excessive bioload.


If you’re thinking of adding more fish, plants, or other aquatic life to your tank you should place them in a quarantine tank for at least two weeks, preferably four weeks. Unless coming from the same tank (i.e. you are transferring 3 neon tetras and java fern from one community tank to another) each individual should be housed in a separate tank. They should be kept under close observation, a healthy adult fish will not have any indications of parasites or diseases before being placed in its new home.

Avoid Overpopulation

An overpopulated tank comes with a plethora of problems including increased waste production, lower oxygen levels, and a higher risk for disease. You should routinely be monitoring your tanks for any signs of aggression that might be due to overpopulation. These could include fin nipping, bullying, or starvation of small fish.


In conclusion, detritus worms aren’t harmful like other aquarium pests but are one of the first signs that something is wrong in your aquarium. With the proper maintenance, you can restore your tank to its former healthy and clean glory and avoid worm-ageddon.

Image References

Featured Image – Naididae By Kai Medina (mk170101) – Own work, CC BY-SA 4.0

1. – Naididae_swimming_2 By Kai Medina (mk170101) – Own work, CC BY-SA 4.0

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