VerMedic: The Fully Reef Safe Vermetid Snail exclusion technology

Vermetid snails can be incredibly destructive in reef aquariums. All it takes is one introduction and in weeks to months you can start to see them everywhere. Left uncheck and with abundant resources, they can quickly take over and stress or even kill corals.

These snails have a unique biology that gives them both a high invasive potential in reef aquariums and a resistance to traditional methods of control. As such, most reefers end up either limiting food (which puts limits on the types of fish that can be kept) or limiting corals to those that can survive the snails chemical warfare. Either of these solutions fundamentally changes the potential of your reef tank.

This is why we are so excited to provide VerMedic to the hobby! Over a year of formulation and r&d has led to this moment in time and we hope that this tool gives hobbyists the ability to take control of their tanks again!

Obligatory aside: Here at Tanknicians we have the experience from having serviced 100’s of real hobbyists tanks. This means our sample size of data is different from the online forums where it’s mainly the elite hobbyists posting and commenting. The real world is much more similar to large beginner Facebook pages. We see what y’all are really doing, and how these tanks are functioning in the wild.

What Is a Vermetid Snail?

Vermetid snails are benthic sessile invertebrates. They exhibit a very unique body plan that most people won’t immediately peg as a snail.

Whereas most snails have a shell and a foot that they use to move that shell across the bottom vermetid snails are only mobile as larvae. Tiny microscopic vermetid snails drift about the tank looking for hard surfaces on which to settle.

Once they’ve identified suitable habitat they glue their shells to the rock and begin creating a tube that reaches out into the water column. From these tubes they secrete mucus ropes that catch particulates from the water.

These snails have the ability to sense particulates and smell food in the water, so reefers afflicted by vermetids will often notice the mucus ropes shortly after each feed or major maintenance event.

Because these snails are entirely benthic, they need a way of preventing other benthic organisms from growing over and smothering them. The primary way they accomplish this is by including noxious chemicals in the mucus.

Besides being a physical irritant the sticky mucus includes pre digestive enzymes and other allopathic compounds which damage coral tissues. The mucus’s effect on corals is magnified by severity of outbreak and also general health of the coral and system.

Very well maintained systems can often survive intense outbreaks of vermetids, albeit with abnormal and slowed coral growth, but the average system will struggle to maintain SPS and most LPS corals where lots of vermetid snails are present.

Why Biological Controls Struggle

A biological control (bio control for short) is basically the method of using an organism to reduce the population of another organism. Don’t want bubble algae use emerald crabs. Have aiptasia? Try a copper band!

We at tanknicians have some moral reservations about the practice of purchasing an organism specifically for the purpose of getting rid of something else growing in the tank that you don’t like. We have also seen how many attempts at using biological controls often yield poor results.

However, we must discuss the common ones here and why they almost always fail at controlling vermetids.

Reefs are incredibly complex ecosystems with a dizzying amount of niches. There is a control on almost every control. There are so many controls that probably most of them we won’t even be able to discover before reefs have gone functionally extinct.

On reefs, to my knowledge, the primary controls of vermetids are likely to be small or juvenile mollusk eating snails, larger fishes, parrotfishes (incidentally) and coral symbiont crustaceans like guard crabs.

Bumble Bee Snails

The most common of these employed in reef tanks are bumble bee snails. However, bumble bee snails really aren’t well suited to the vast majority of reef aquariums and probably are an animal that ought not be sold nearly as often as it is.

Bumble snails are a type of opportunistic whelk. They’ve evolved a drill like radula that can burrow holes through other mollusk skeletons. They then feed on the flesh of the snail from the inside out.

However, if uneaten food is available, they will take the path of least resistance and eat the easy meal. Also, it is our belief that an adult bumble bee snail is going to be far more likely to target a larger snail like a turbo or trochus before attempting to eat a small vermetid.

While you will find forum posts with people swearing bumble snails controlled the vermetids in there reef, and perhaps it does sometimes happen, in over 20 years of LFS experience and 15 years of maintenance experience I have personally never seen it and only had it credibly reported once.

More often than not, people purchase bumble snails only to notice that they have zero impact on the vermetids.

On a number of occasions hobbyists have shown me pictures of bumble bee snails feeding on larger turbos or torches snails.

We’ve hypothesized that it may energetically make more sense for very juvenile bumble bee snails to eat smaller vermetids, and that perhaps people would have more success employing small AQ specimens the way coral spawners use baby tuxedo urchins.

Larger Fish

Larger fish are going to be tougher in a reef tank for controlling vermetids. A fish capable of killing and eating a vermetid is also capable and probably willing to eat and kill desirable corals and invertebrates in your aquarium.

Very few reef tanks are large enough to house these larger animals as well, leaving the nano, mid and large sized reef tanks out of luck.

These fish will also become less effective in tighter spaces, meaning as corals colonies grow larger and denser the vermetids will find sanctuary deep in their structure.

Prevention – Easier Said Than Done but worth the effort

We pride ourselves on our coral QT chops. We use very destructive methods to clean corals and have found them to be very effective.

However, very recently we noticed something interesting. We acquired some very healthy frogspawn with thick tissue bands 3-4” down the skeleton. For the last stage of QT the bare skeleton on these frogspawns was debrided and we glued them to plugs.

Several weeks later we had some tissue recession the bands were creeping upwards. Beneath the tissue we found a few vermetid snails.

The fact that they can be capable of hiding within the healthy tissue bands of corals makes them potentially impossible to have 100% confidence of removal without extended months long quarantine.

While that is best practice for a variety of reasons, it is untenable for most hobbyists.

There are no effective dips during the quarantine process that can rid a frag or colony of vermetids. Vermetids can close themselves in their tubes by sealing their operculums (perhaps to there own undoing!!)

Very strict quarantine of anything wet with a hard surface is by far the best defense and something we should all do, but for those that don’t and for those that already have them, or for those that get them anyway, VerMedic is the answer.

Other Methods of Dealing with Vermetids in a Reef Tank

Many reef tanks ‘coexist’ with naturalized vermetids. However in a lot of these cases the tank is fundamentally altered.

Some reefers attempt to limit numbers by reducing the amount of particulate food in the environment. Keeping detritus levels low, forgoing pellets or flakes, and rinsing frozen foods before feeding will limit the population in an aquarium.

Unfortunately, that will also limit the populations of other particulate or planktonic feeders, necessarily limiting the ability of reefers to keep fish and corals that require small zooplankton as well.

The other method reefers use is to give up on the corals that won’t survive the vermetid infestation and shift the focus of the reef to fish and hardy corals.

Both can yields beautiful tanks, but have obvious drawback.

Some people have recommended fendbendazole flakes or coral snow for vermetid snail control.

Neither of these methods have been effective for us or others that we’ve know to have tried them but the theories behind how they work seem sound.

Fendbendazole will kill snails, we’ve used in tank treatments to deal with hydroids and Xenia infestations and it’s a regular part of our coral Qt process.

The fendbendazole infused flake food is supposed to target the medication to the vermetid without dosing the entire tank with a lethal dose that would damage other desirable inverts and corals.

Coral snow is purported to fill the vermetids with junk filler negative calories.

However I’ve known reefers to forgo dry foods, filter frozen foods, and dose daily reef snow with no impact.

Again, we aren’t saying that there aren’t some reefers somewhere that have successfully used any of these methods, just that from what we’ve seen and from our experience that is at best uncommon.

VerMedic to the Rescue

VerMedic is a white powder specifically ground and sized to the particulate size on which vermetid snails prefer to feed.  These micro-particulates physically interfere with vermetid snail feeding mechanisms prompting the snails to retract into there calcified tubes and seal there physical barrier. Simply dose the water with VerMedic following the instructions. after 3-5 applicationf of VerMedic the feeding tubes should be fully sealed preventing the damaging behavior.  

Infestation level will dictate the concentration needed, however typically 3-5ml/100g is a very effective application volume of dry vermedic to be dispersed into the display tank.

Optimal application window is every three days.

Once a week is ineffective and more frequent doesn’t seem to improve the efficacy, its better to simply increase the application amount if infestation population is very heavy.

In our testing we have overapplied the product more than 10x- however you would be wasting your money and the product at those higher amounts 🙂

Tips for optimizing VerMedic

1. Keep Plenty of Flow in the Display

• You need to turn the return pump off so that you don’t filter out the VerMedic.
• Vermetid snails require good flow to sense the level of particulates in the water.
• With inadequate flow they may not have the feeding response required for contact with VerMedic.
• Run powerhead, and if you aren’t noticing good feeding responses consider adding more flow, or micro bubbles.

2. Don’t use VerMedic When Other Particles or Food Are in the Water

• In order for VerMedic to be most effective, you want the snails interacting with just VerMedic.
• Diluting the VerMedic with other particles will make VerMedic take longer to seal the tubes.

3. Entice a Stronger Feeding Response Without Diluting the Webbing

• You can stimulate a feeding response by disturbing a tiny patch of sand.
• If you have detritus in your sand, many of these particles will be enticing to the snail.
• However, when you do this those particles can take the place of VerMedic in the mucus ropes, effectively watering down the concentration delivered to the snail.
• Instead, consider defrosting frozen food in water and waiting for all the food to settle.
• Wait 5 or more minutes so the finer particles have time to settle as well.
• Then gently and slowly pour the liquid while attempting to prevent the food and fines from entering the tank!