Vermetid Snails: The Ones You Don’t Want in Your Tank!

Vermetid Snails Infographic

For vermetid snails, you almost need to erase everything you know about snails from your mind. Everything about this hitchhiking species is outside the box and highly irregular when compared to its gastropod cousins.

What Are Vermetid Snails?

Vermetidae is a family of snails, 160 or more, all of which are sea snails. They often go by other names. These include:

  • Vermetid snail
  • Worm shell
  • Worm snail

The nicknames they have earned might give you a good idea of what these unpleasant visitors look like… a bit ‘wormy’!

What Do Vermetid Snails Look Like?

Vermetid snails don’t really look like any other kind of snail, in any kind of way. They look more like worms, hence the name, except you might not see them often. They sit in the base of their calcified tubes. That’s what you’ll likely see, building up and growing slowly.

The tubes can be all sorts of weird and wonderful shapes, included curled around, shaped like a tree with branches, and more.

Different species of vermetids will grow to different sizes, but the tank parasite can grow to between 0.5 and 4-inches (1.27 to 10.5 cm). Some of them can get really big!

What Do Vermetid Snails Eat?

These weird and often unwanted marine gastropods eat via a ‘fishing’ method. Using a net made from mucus case out from the tube, they can catch teeny-tiny food particles that they then eat, such as fish poop, decomposing organic material, algae, and plankton.

Vermetids can’t eat unless water moves food particles around, so they won’t survive in a still body of water.

How Do Vermetid Snails Reproduce?

Not only does this snail fish for food, but it also fishes for babies! Well… sort of.

The males will essentially let their sperm float away into the water. The females send out that fishing net and collect the particles, sucking it all into his mouth and then moving it to where it needs to go (mantle) to fertilize her many egg capsules, which each contain several eggs, up to 40 or 50.

How Bad Are Vermetid Snails?

For many people, most in fact, vermetid snails are very bad. Some might go as far as to say that they were the worst things ever to have in a tank.

If you have vermetid snails in a tank with coral it won’t be long before the coral starts to die. Vermetids will latch on to corals, building their calcified tube shells on them. This can lead to deformed corals and even injured corals.

When the snail feeds, it does so with a fishing net made out of mucus, which can also have adverse effects on coral, essentially poisoning or irritating it.

This unwelcome visitor will also consume food that tank mates are supposed to eat, including other snails. And then there’s the reproduction problem

saltwater aquarium corals

How Did Vermetid Snails Get in My Tank?

These critters are hitchhikers, which means they enter your tank via other means. This usually means already attached to other snails, latched on to coral or ornaments, and even sometimes on plants.

This is why it’s important to properly prep anything you plan to put in the tank, using thorough cleaning and quarantine approaches. Where possible, give ornaments and snails a once-over with a wire brush to knock off any unwanted add-ons.

Sometimes, teeny tiny vermetid snail eggs can be present in water with live fish, live snails, and other types of live-in-water animals. You may not see them, but when the water and animal(s) are introduced into the water, the eggs are too… where they will soon hatch.

How to Remove Vermetid Snails

You do have a few options when it comes to getting rid of vermetid snails once they’ve made themselves comfortable inside your tank.

As with all problems, the earlier you deal with it, the easier it will be. Once the snail has latched on to a surface and started to build that shell substitute tube, they won’t move until they die. The tube will also get bigger and bigger, and sometimes the snail will decide it doesn’t like its existing spot and move to another one, causing another patch of damage.

Dead snails and tubes that are left inside the tank will also alter the delicate water parameters, such as pH level and balance of nitrogen and other compounds.

Removing vermetids comes down to literally physically removing them, either by killing them in the tubes and then removing the entire thing, or taking latched-on items out and using force to remove the snails.

As with most things in life, prevention is much better than cure. It’s easier to stop vermetids getting into your tank than it is to get rid of them once they’ve already moved in.

What Eats Vermetid Snails?

Not many things in your tank at home are likely to eat vermetid snails, but some tank mates can help with an infestation. Coral crabs, for example, have been said to help with the mucus fishing net problem, stopping the matter from coming into contact with coral. Emerald crabs may also eat the gastropods, but it’s not a guarantee.

Some snail species are thought to eat vermetids occasionally, including bumblebee snails. You must remember, though, that the worm-like snail is hidden right at the bottom of the tube it creates. It’s quite difficult for other animals to get hold of them!

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