Why are Vermetid snails a pest in your Aquarium?

Vermetids feed by releasing a mucous net.  Unfortunately the mucous net causes horrible impacts when it lands on coral tissue – killing, degrading or rotting the coral.  Then you end up with an exposed skeleton leaving it available for colonisation for nuisance algae.  So, it is really important to get rid of these pests as soon as they are identified.

How can I tell the difference between a Vermetid snail and a Polychaete worm?

Vermetid snails are a gastropod but can appear like a Polychaete worm.  However, they have irregular tubes, that often coming out of your base rock or coral.   Their casing is a creamy brown with a little reddish hue when in water, whereas the Polychaete worm’s casing are more white /purple in colour.

Another method is to look for the posterior base that has a lot of torsion (twisting).  And the anterior end potentially has a mucous net, and two antennae from the snail coming out of it (instead of a beautiful fan for the worm). 

How to remove Vermetid snails from your Aquarium 

They are very resilient, so just taking their casing out of the tank doesn’t kill them. The first step is to identify that they are indeed a Vermetid snail.  Some people even go to the extent of not feeding their coral and then adding some particulate coral food so they can see the mucous net come out.  Others make use of very clear water, ozone or microbubbles first.  But the key is that posterior base with torsion.

If you have a lot of them, then you need to search out the breeding mother colony one as it must be removed or the removal of the smaller ones will not make an impact.

Successful methods, in varying degrees are:

• Gluing the anterior end with coral glue or putty – this stops food and reproducing from occurring. However, they have been known to grow around the glue or even through the putty.
• Using coral cutters and cut them out. Effective but sometimes difficult to achieve if you can’t get to the base.
• Lancing the casing – by getting a very thick needle and puncturing through the body of the casing and snail, but you must puncture into the base as it can retreat right into it.
• Acropora crabs could be a predator. Unfortunately, we haven’t found a benefit from Wrasse as a predator.  Larger fish may work but they also can cause problems on your coral anyway.
• Using lasers to burn the tissue has been successful – unfortunately in Australia we don’t have access to this tools!

And remember to make sure to check new coral as you get it – prevention is always better than the cure.

Want to see our examples, then watch our video at https://youtu.be/eO-FW_a7kMU