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Have you spotted some tiny white worms swimming around in your fish tank? If you’re worried and looking for advice on how to solve this problem, you’ve come to the right place!
After reading this article you should feel a whole lot better, and know exactly how to get rid of detritus worms in your aquarium.
So sit back, relax, and let’s get learning!
What Are Detritus Worms?
Detritus worms are harmless creatures that are very common in aquatic environments and aquariums. These segmented worms(like earthworms) are technically known as annelid worms.
They are tiny creatures that actually form part of your tank’s natural clean-up crew because they feed on animal waste and any leftover food. By processing decomposing materials, these worms help to keep your aquarium clean and safe for your fish.
Many fish keepers will be completely unaware that these aquarium animals even exist because the worm population will usually stay in balance.
In many aquariums, these worms live hidden away in the substrate, but when their population gets out of control, they can be seen in the water column and up at the water surface.
How Do I Identify Them?
Detritus worms are not a specific species, but rather a group of worms from the annelid family. The most common detritus worms that are seen in aquariums are tiny creatures that are a whitish color and wriggle like snakes. Small reddish-brown worms are also pretty common.
Detritus worms measure up to about an inch long but are generally much smaller. They are usually seen in your substrate or in your filter media.
These little guys can also be seen up in the water column and against the aquarium glass sometimes, especially when there are no predators around or if dissolved oxygen levels are low, which forces them to the surface.
Other Aquarium Worms
Detritus worms are not the only worms that can be found in aquariums. Unfortunately, not all types of aquarium worms are as harmless as detritus worms. Here are some other worms to look out for:
Planaria worms are another common aquarium worm that can be a bit of a pest.
Unlike detritus worms, planaria worms are not from the Annelid family but are actually flatworms. These flattened worms have a pointed face and two distinct dark eyes.
Camallanus worms are bad news. These parasitic worms are harmful parasites that can infect a variety of tropical fish species.
Camallanus worms are nematodes which means they are not from the same family as the other two types of worms we’ve already discussed. They can also be whitish or reddish-brown.
The big difference between them and detritus worms is that they live inside your fish, rather than in the substrate.
How Did I Get Them In My Tank?
Detritus worms sneak their way into our fishtanks when we transplant objects, water, plants, and animals from other tanks or freshwater environments. The most common routes these worms take into our fish tank are:
- Transplanted in gravel or substrate
- Transplanted in a filter or filter media
- Introduced with new aquarium plants
- Introduced with new fish and other aquarium animals
How to Avoid Introducing Them
Now that you know how detritus worms find their way into the home aquarium, let’s look at a few ways to prevent this from happening.
As a general rule, never introduce pond plants or anything to your aquarium that you’ve found outdoors in a pond, lake, or stream. Natural waterways are filled with all sorts of tiny organisms that you might not want in your fish tank.
Unfortunately, you can also introduce pest animals when adding things from friends’ tanks or from your local fish store. The two most likely sources are used gravel and filter media, so make sure to avoid transplanting those to your tank.
Adding fish and live plants is another common source of aquarium pests. When it comes to plants, the best way to avoid this issue is to add tissue culture plants.
Author Note: These are grown under special lab conditions to be pest-free. They aren’t always easy to find. I always recommend buying fish and other livestock from trusted sources locally if you can. If you can’t find it locally, check out my best places to buy fish and plants online to see where to get the best quality fish.
Why Are There So Many Worms In My Tank?
Before you do anything about the worms in your tank, you first need to look at the cause (video source). Even though detritus worms are harmless and actually very good for your tank, you shouldn’t be seeing too many of them.
A detritus worm infestation is usually a sign that something has gone wrong in your aquarium. By acting as a red flag, these tiny creatures prove again to be pretty handy!
Detritus worms multiply when water conditions are poor. There are 3 main factors that cause poor water quality. Let’s take a look at each of those now:
There is a limit to the size and number of fish that you can keep in any aquarium. There are a few things that go into determining just where that limit lies, but as a general rule, the larger your aquarium, the more fish you can keep.
Fish produce waste, and as this waste builds up in the tank, water quality decreases. The amount of animal life and waste in your tank is called the bioload, and it is not only fish that affect this.
Shrimp and snails also add bioload to your tank, but usually much less than fish. The greater the bioload in your tank, the faster water quality will deteriorate.
Any fish food that is not eaten by your fish will sink to the bottom of your tank and decompose there. This provides a great food source for detritus worms and they will begin to multiply.
Uneaten fish food doesn’t only feed the worms though, it also breaks down to form harmful toxins in the water that can harm fish and cause algae growth.
Lack Of Maintenance
Even if you have just the right number of fish, and you’re feeding them only what they can eat, you will still need to do some regular aquarium maintenance to keep your water quality in the ideal range. Falling behind on your maintenance is a common cause of detritus worm increases.
How To Get Rid Of Them
You can think of detritus worms as a symptom, rather than a problem. Now that you know what causes detritus worms to multiply in your aquarium, you also know how to reduce their numbers. I’ll provide a few pointers below. For those who are visual learners, here is a video by BB’s Beasties that explains her process.
How To Fix An Overstocked Fish Tank
If you have too many animals in your fish tank, you have a few options. Let’s explore those now:
- If your tank is only slightly overstocked, you might be able to get away with installing a larger filtration system and increasing your tank maintenance
- You could move your plants and animals to a larger aquarium
- If you have a community aquarium, you could buy another tank of the same size and move some of the livestock over
- As a last resort, you might need to rehome some of your fish by giving them to friends or returning them to the pet store. Never release your aquarium pets into local waterways!
Is Your Filtration System Strong Enough?
Poor filtration is often the cause of water quality issues. As a general rule, you should select a filter that can process the total volume of your aquarium water between 4 and 6 times every hour. Canister filters and aquarium sumps are going to be the largest filters you can purchase and will have the most filter capacity.
Are You Overfeeding Your Fish?
With the exception of herbivorous fish like otos, healthy fish do not need a constant supply of food. Providing food once a day is usually more than enough to satisfy your pets’ feeding habits.
The speed at which different fish eat varies, but if they can’t finish all the food in a few minutes, you’re probably feeding them too much.
How To Stay On Top Of Water Quality And Tank Maintenance
Poor water quality from a lack of maintenance is one of the biggest causes of detritus worm increases in your tank. Here’s some basic information on how to keep your water quality in great shape.
To be able to get your water parameters in order, you’re going to need to take some measurements. If you don’t already have a water testing kit, I would suggest picking up a set now.
You don’t need the most advanced scientific instruments to do this, something like the API master test kit will do just. Alternatively, you can get away with some simple strip tests.
Whichever test kit you have, it’s important that you can measure the following parameters:
These nitrogen compounds are the products of decomposing organic waste like uneaten fish food and fish waste in your aquarium. Each of them is toxic to your fish, and your test results should not show any ammonia or nitrites if your tank is cycled.
Nitrates are less toxic but should be kept to below about 20ppm at most. To manage the nitrate levels in your tank, you will need to perform regular partial water changes or consider nitrate removers.
Every week or two, you should change out a percentage of the water in your aquarium for new, clean water. This resets the nitrate levels in your tank and keeps the water safe for your fish.
The amount of water you will need to change depends on your filtration system and bioload. Use your test kit to measure the nitrates in your water before and after a water change.
If the nitrates are below 20ppm before doing a water change, you haven’t left it too long. To start out, you could try a 25% water change every week and make your adjustments as necessary.
Other Aquarium Maintenance
Detritus worms feed on fish waste and leftover fish food in and on the substrate at the bottom of the tank. The best way to remove these food sources from your tank is with a gravel vacuum.
Use your gravel vacuum to siphon out water and excess waste from the aquarium substrate level when doing your water changes. Substrate vacuuming can also physically remove some of the worms from your tank.
From time to time, you will need to rinse off or replace the sponge and media in your filter. Be sure to rinse off your sponge in old tank water. Tap water contains harmful chemicals like chloramine that can kill off your beneficial bacteria.
Live plants are great for soaking up excess nutrients and maintaining the proper oxygen level in your aquarium. If you grow live plants in your tank, be sure to remove any dead leaves and other plant waste before they can spoil in the water.
What About Poisons?
You might think the obvious choice for controlling the detritus worm numbers in your tank is to use some kind of poison.
The problem is that chemical treatments can be very harmful to other tank inhabitants. This method is probably not going to prevent the problem from occurring again in the future anyway.
Using a dilute mixture of hydrogen peroxide can be useful for killing off worms, but this can be risky for some of your other animals and should only be used as a last resort.
Introduce Some Predators
Another great way to prevent detritus worms is to introduce some animals that will eat them.
If your water quality is great but you’re still finding these worms all over the place and just don’t want them around, it might be time to add some predators.
Author Note: Most carnivorous fish will happily eat detritus worms, and bottom feeders like corydoras catfishcan be very handy for keeping the worm population in check.
Are They Harmful To Shrimp?
So we know detritus worms are harmless to our fish, but what about other animals like shrimp? The good news is that these worms are perfectly safe to have in your shrimp tank. Other inverts like snails are equally safe.
Should I get rid of these worms?
If you have a detritus worm problem, you should focus on improving your water quality, rather than targeting the worms specifically.
By doing so, you’ll improve the health of your aquarium and the fish and other animals that live in it. At the same time, the worm population will decrease. Now that’s a win-win!
What will eat them?
Most carnivorous or omnivorous aquarium fish will see detritus worms as a tasty snack!
Bottom feeders like corydoras catfish and loaches will sift through the substrate to search for these creatures, but worms that swim up into the water column will be eaten by just about any small fish.
Can you starve them?
Yes, by reducing the amount of detritus (fish waste and uneaten fish food) available to the worms, their population will naturally decrease. This is a safe and effective way to fix your detritus worm problem.
Are they bad for my aquarium?
Detritus worms are great for your aquarium, and they don’t harm fish. They break down waste and uneaten food which makes them safer for your fish and provides more nutrients to live aquarium plants.
If you’re seeing a population explosion, the worms themselves are not the problem. The tank probably just needs a thorough cleaning and more frequent water changes.
A detritus worm infestation might seem like a huge deal, but understanding the cause is the most important step to solving this problem.
In conclusion, detritus worms are nothing to be afraid of, all you need to do is get your water quality under control and give your tank a proper cleaning and the problem should solve itself. Happy fishkeeping!
Mark is the founder of Aquarium Store Depot. He started in the aquarium hobby at the age of 11 and along the way worked at local fish stores. He has kept freshwater tanks, ponds, and reef tanks for over 25 years. His site was created to share his knowledge and unique teaching style on a larger scale. He has worked on making aquarium and pond keeping approachable. Mark has been featured in two books about aquarium keeping – both best sellers on Amazon. Each year, he continues to help his readers and clients with knowledge, professional builds, and troubleshooting.
Very interesting. We are just noticing a large population of detritus in our tank. We only have one catfish in it.
We are concerned with the tiny worms because we haven’t seen them before.
Worms are very harmful for our aquarium. I have also faced the similar problem. My main main tips are:
Change the water and other objects
Put aquarium fish that eat detritus worms
Proper maintenance and care
Use algae scraper and water siphon
Use gravel vacuum
Use a little amount of Hydrogen Peroxide
Improve your aquarium’s filtration system and feeding practices