Introduction to Sundial Snails: 

Heliacus variegatus is commonly known in the aquarium hobby as a Sundial snail or box snail. These nocturnal snails are known Zoanthid predators.


What a Sundial snail looks like:

These snails are typically white and black, occasionally having an orange tint and a little protrusion on the back side, often referred to as a rattlesnakes tail.


Signs of infestation: 

Viewing sundial snails in your aquarium.  Additionally, one by one, your zoanthids will begin to slowly disappear.


Life Cycle of Sundial snails:

Little is known about sundial snails’ reproductive cycle other than they reproduce sexually making large infections rare.



A quarantine tank is the easiest way to prevent these ugly little reef critters from destroying your Zoanthid based reef tank. Ideally, Zoanthid corals should be left in quarantine for 3 months.

During the quarantine time, you should view the coral on a daily basis and watch for Sundial snails. Remember that Sundial snails like to stay hidden in the polyp mat and typical come out when the lights are off.

Whether or not quarantine is an option, a dip in CoralRx is highly suggested.



Treatment should be done in a quarantine tank.

  1. The first step is to move the affected corals to a quarantine tank; the quarantine tank should have good light and water flow.
  2. Next, take your coral out of the main tank and dip it in Coral Rx.
  3. While the coral is in CoralRx take a turkey baster, and blast the coral with the dip. Making sure it is getting in between the polyps and the underside of the coral. Do this for approximately 5 – 10 minutes.
  4. After 5 – 10 minutes, remove coral and discard the coral dip.  Do not reuse the coral dip as parasites may release toxins.
  5. Rinse coral with clean saltwater and return to a quarantine tank.
  6. Repeat every 4-8 days till no more snails are found. Leave the coral in your quarantine system for an additional 3 months before moving back to your aquarium.

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