In a nicely set up reef tank, the chance for parasites and pests to invade are not uncommon. Some can be beneficial, while others may not. And speaking of the non-beneficial ones, the small and “worm-like” Vermetid Snail is the one of them that you should keep an eye out for.

This variety of invasive Snail is a big problem for reef tanks, especially if you have corals and sponges in it. Even for a professional, they are a nuisance as they are quite tiny and hard to detect.

Additionally, even if you are very careful, they can invade your tank in numerous ways. But how will you know if your tank has a Vermetid infestation? If so, how can we prevent it, and even get rid of them?

There are many ways to detect and get rid of these Vermetid Snails. We will help you understand the ways and habits, so you can prepare yourself if you ever face this situation.

About the Species

Quick Species Facts
Family Vermetidae
Other Common Names Worm Snails, Worm Shells
Superfamily Vermetoidea
Origin All over the world
Max. Length 4 inches (10.2cm)
Type Saltwater (Marine)

What Are Vermetid Snails?

Vermetid Snails are not a type of snail, but a group of gastropods in Vermetidae taxa. These are quite small and mostly occupy saltwater locations (marine).

In addition to that, there are about 160 different genotypes in this family, and they look shockingly similar to one another. The only way to identify the difference is by using DNA fingerprinting, or through probes and markers.


They are very well adapted to different marine conditions and live in many tropical and subtropical habitats, to warm temperate coastal regions, with water temperatures ranging from cool to moderate (reference). So, it is hard to say anything about their preference for location choice.

They live at depths of about 10 m in the reefs, but some can even be found much deeper on the ocean floor. (reference)

They are at first difficult to detect because they don’t have the signature round shell of a Snail. People just think it is a part of the coral because they attach themselves to it.

In addition to that, these Snails may look like they are living in these tubes, but in fact, they live at the bottom of these tubular structures.

These act as a passage for them, and they can even close the mouth of the tube with an operculum. But the operculum is not present in all species of Vermetid Snails.

How Big Can Vermetid Snails Get?

The size of Vermetid Snails depends upon the individual. Some varieties can grow up to 1 cm or less (0.4 inches), but many do attain a size of about 10 cm (4 inches). Some can even exceed that limit, but it’s quite rare.

Appearance Of Vermetid Snails?

Outer Features

They don’t look like typical snails as their shells are not rounded and spiral. It looks like a tube protruding out from a surface.

It is so distinct from the average snail that many aquarists confuse it with other organisms such as tubeworms or Polychaete worms.

Their tubes are almost smooth and straight, but you may also see some spiraling at the base. Some can even have branchings from the existing main tube or the base of the attachment.

The surface of the tube is almost smooth, but the growth striations can be distinctively felt if you touch them.


Their shell color varies from cream to brownish, with the presence of much darker stripes. In some varieties, the dark lines may be clearly visible.

How Do Vermetid Snails Obtain Nutrition?

Their way of getting nutrition is unlike any snail that you see every day. They also do not eat like regular Snails; they are filter feeders. This is an uncommon feature that is seen in these families, but the way they are built justifies this anomaly. (reference)


They build a net out of their mucus-like thing which originates from the opening of the tube and extends quite a distance. These net-like constructions are the first thing you may notice if there is a Vermetid Snail present in your tank.

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Now, these mucus nets catch the food right out of the flowing water. These are sticky, so food particles get stuck to them, which are then later consumed by the Snail.

These mucus nets are produced by a special organ or gland present in their mouth, which is then extended out using a special tentacle. The size of these varies, which depends on the water current of the reef.

Moreover, the size of these nets can also vary depending upon the size of the Snails. Bigger ones tend to cast bigger nets as they require more nutrition. Its surface area can range from 3 square centimeters up to 10 square centimeters.

This net is extended out during the feeding session and remains open for 30 to 40 minutes depending upon the number of food particles caught in it. After this, it is pulled inside and the food matter is consumed by the Vermetid Snail.

According to a research paper, when these Snails were kept in a closed system such as a water-filled container, they failed to produce these mucus nets.

However, it was concluded that they require a steady flow of water to extend the nets, and so the extension is dependent upon the direction and force of the current. The higher the flow, the bigger the net created by these Snails. (reference)

Their diet includes-

  1. Planktons- Phyto- & Zooplanktons
  2. Tiny Algae
  3. Detritus matter
  4. Free-floating food particles

Reproduction In Vermetid Snails


Even though they remain idle most of their lifetime, they have a unique way of reproducing, which enables them to successfully invade and increase their population.

The male Vermetid Snails produce spermatozoa that can stay suspended in the water for a long time. These sperm cells travel along with the current, which is then caught up by the net of a female.

These are now taken up when the net is retracted, and stored in special pouches inside the mantle cavity. This mantle cavity possesses multiple eggs in small packets ready for fertilization by the male gametes. Each packet may contain numerous eggs.

Fixation & Calcification Of Shells

After fertilization, the eggs hatch and release many Vermetid Snail babies, which stick to a solid surface or substrata, as soon as they are released.

Generally, this attachment process is usually completed within 24 hours of hatching. However, in the case of failure to find a proper substratum, the attachment can be delayed by a few days.

The baby Vermetid Snails develop very fast, and show adult morphological features in a matter of days, following a successful attachment. (reference)

They form the shells by the process of calcification rather than the typical mineralization used by other families of Snails.

How Do Vermetid Snails Get In Our Tanks?

Just like many other unwanted gastropods, such as Ramshorn Snails, and many more, they are accidentally introduced into people’s aquariums.

So, people go to shops to buy decorations and accidentally pick rocks and stony corals, infested with attached Vermetid Snails.

In other cases, it can be introduced into tanks as eggs, freely present in the water. This mostly happens during the purchase of fish, or other marine animals or even plants.

These eggs then stay in the water for days as they are incubating, till they are mature enough to hatch.

Damage Caused By Vermetid Snails To Reef Tanks

Before we go into their disadvantages and the damage caused by them, let us first see some of the beneficial sides of these snails.

Useful For The Environment

Vermetid Snails in their natural environment are known to be some sort of bio-constructors i.e., they help in the formation and regulation of reefs.

Alongside it, these Vermetid Snails have also been used as a replacement for bioindicators. How, you may ask?

Well, marine biologists and scientists study the behavior they are exhibiting by comparing it to the distribution they are in. Then they can measure the changes in ocean water along with some other parameters as well.

Damages caused by them

However, it just becomes the opposite when present in artificial surroundings. These species can devastate coral reefs. If these snails are not removed in time, it may even lead to the death of corals.

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The main reason behind this is that Vermetid Snails deprive the corals of their food. As discussed before, these Snails are filter feeders, just like corals.

However, their technique of acquiring free-flowing food particles is much more effective than the corals. These Snails are always a step ahead of them and corals, failing to match their competitive nature, die due to lack of nutrition.

However, this situation does not occur all the time. Some Vermetid Snails cause less damage than others. Some Snails may not be that much competition.

Another phenomenon that is sometimes seen that the corals start to grow over their shells. This can cause suffocation and deprivation of food for the Snails, which ultimately kills them.

Vermetid Snails use calcium present in the water to make their shells. So, they single-handedly decrease calcium levels in the water, which is bad for other marine organisms.

However, having said that, whatever the degree of infestation may be, you should always try to remove them as soon as possible from your tank. The different methods of removal are discussed in the next section.

Eradication Of Vermetid Snails: Eight Methods

It takes a bit of work to properly get rid of them. Here are a few things you can use to get rid of them:

  • Removal Using Hands

It might seem a bit peculiar, but removing them manually is one of the best and safest ways. You can use screwdrivers, knives, coral cutters, scalpels, or other sharp objects to cut it out.

If you are facing difficulty locating their base, then you can also use a magnifying glass. It is important that you remove them from the roots, all the way through. If you only cut away the tube section, they will regrow it back.

Plus, these gastropods live at the spiraled base of the shell. So, it is important that you completely remove them from the base.

Caution: Use sharp tools carefully and wear protective gloves. If possible, use them under supervision.

  • Puncturing their shell

This method can be a bit gut-wrenching for some people as it requires you to kill the snails directly by puncturing their shells. But this is a good way of making sure they are completely dead.

Different kinds of tools can be used, such as big needles, awls, etc. which are sharp enough to go all the way through their shells, killing the Snail residing at the bottom.

Beware- Remove the dead Snails from the tank as soon as possible because it can lead to an increase in nitrogen/ammonium levels in the water.

  • Using a glue

You can use strong glue to block the opening of the shell. This will ensure that the Snail suffocates inside. Along with that, it will also not be able to release its eggs into the water. This will stop further spreading.

However, you should keep in mind that the dead body inside will start to decompose. And if the shell breaks after that, for any reason, it can increase the ammonium levels, and release harmful bacteria into the water.

So, after a week or so, when you think it’s dead inside, you can carefully scrape off the shell from its base so it won’t cause any problems.

  • Starving them out

This is another technique of getting rid of these pests from your reef tank. This is where you starve them to death by limiting your feeding.

But before doing this, keep in mind that the way of acquiring nutrition for both corals and Vermetid Snails is the same. So, your coral may face starvation also.

The way to counter this is by spot-feeding or target-feeding your corals. This will make sure your corals get nutrition, but the Snail doesn’t.

  • Using Coral Snow

However, another way of doing this is by using liquid filter media, commonly known as Coral Snow. It looks like clay and acts as a strong absorbent in the water, sucking in all the food particles and making the water clearer.

This process can take time, but it will ensure that all these Snails, even the hidden ones, gradually die off. Also, remove their dead remains after the results have been achieved.

  • Introducing Natural Predators

This is a good method if you don’t want to go through the hassle of removing them. This also ensures the prevention of left-over dead carcasses in the water with the previous methods.

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Although the number of natural predators is low, there are still some that can easily be purchased from any local store. Some of them are-

  1. Bumblebee Snail (best)
  2. Yellow Coris Wrasse
  3. Peppermint Shrimp
  4. Crabs (Coral Crab, Emerald Crab)

Even though they eat Vermetid Snails, it is not at the top of the list on their menu. The only way to make sure they eat them is to starve them a bit. It is like a game of chance. So don’t expect 100% success, but it can be considered a good alternative.

  • Hypo-salinity/ Osmotic shock method

Lowering the concentration of salts or diluting the saline water is another way of getting rid of these Snails. This lowers the osmotic pressure in the water, causing the Vermetidae to die off slowly due to reduced osmotic pressure.

This is a less popular method because it causes the other marine invertebrates to die along with the Vermetid Snails. If you are ready to face this situation, you can try this method.

  • The Unconventional Laser

It may sound odd at first, but strong lasers can also be used to get rid of Vermetid Snails. If you own a strong, high-watt laser, you can use it to kill them from the inside.

The only thing you need to do is focus the beam of light right at the base of the shell. This will literally burn the Snails and cook them from inside. Then you can remove it from the tank at your own leisure.

Using Muriatic Acid (The “Big Guns”)

Now, if any of the previous methods didn’t work out for you, it is time to take out the big guns, i.e., Hydrochloric Acid (HCl).

You may also know it as Muriatic Acid, as this name is quite famous among aquarists. Both are the same, the former being the chemical name.

It is highly corrosive in nature and it is highly recommended that you use safety gear, which includes-

  • Protective gloves
  • Protective eyewear
  • Respirator (optional)

Protective gloves and eyewear are a must, but the respirator is optional because it depends on how you work with the HCl.

It is better to take the tank outside so the fumes don’t fill up your house. If the concentration of HCl is moderate to high, put the infested coral in it for a few hours. If it is diluted, you can keep it dipped inside for a few days.

Moreover, you should keep in mind that it is very damaging to the corals and sponges as it will bleach them rigorously.

It is also damaging to other decorations as well if it is done inside the tank. So, wash the corals and sponges with water before returning them to the aquarium.


If you want to avoid such infestations, you can take a few precautions that will help you control the uncontrolled growth of Vermetid Snails. This will save you money and time.

  1. If you are buying anything from the store to put in the tank, ensure to quarantine it first in a separate tank no matter how clean it looks.

Sometimes the eggs can stay hidden in cracks and crevices. Quarantining will make sure these eggs are killed off, along with other pests.

  1. Isolate your existing corals and sponges every few weeks and put them in a disinfecting bath. This will help stop the uncontrolled spread.
  1. Keep a few natural predators in your tank, as mentioned in the section above.

Frequently Asked Questions

Are Vermetid Snails and Tube Worms the same?

No, they are very different marine organisms, even though both of them look very similar. The Tube Worms have feathery extensions at the corners of their mouths, but Vermetid Snails have a big net made up of saliva.

Does Coral Dip kill Vermetid Snails?

Even though Coral Dips are used to remove the pests from coral surfaces, they will not kill the Snails. It is not potent enough to kill these gastropods.

Conclusion: Do Not Be Worried

Vermetid Snails can really be a pain to deal with if they start multiplying. If you ignore them for a long time, the damage caused by them will be irreversible.

Make sure you are taking all the precautions. Plus, keep a few natural predators in the tank if you suspect Vermetid Snails are growing on your corals and sponges.

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 aquarium manufacturers as a consultant
  • Organized and hosted workshops on freshwater fish keeping at retail stores, educational facilities, and libraries
  • Released content for the amphibian community through her writings

Educational Highlights:

  • BSc Honors in Wildlife and Fisheries in 2011 (University of Northern British Columbia)
  • Completed her undergraduate thesis on the effects of zoochlorella supplementation on the growth and health of fish.

Writing Experience

Miss Crosby is a Freelance blogger; many of her articles are posted online on various blogs. She has also written a few short articles for "Tropical Fish Hobbyist Magazine" in the past. She is a regular contributor to Her education, first-hand experience with fishkeeping, and in-depth knowledge in aquaculture make her one of the most competent writers in the industry.

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