What are they

Scubapat · Nov 16, 2022

I thought they were snails, but now I am concerned. I was told by the LFS they were a worm and a big problem.

WheatToast · Nov 16, 2022

Looks like limpets, which are flat snails.

ISpeakForTheSeas said:
Normal limpets are totally fine, but there's some speculation about Keyhole Limpets possibly eating SPS corals. If yours is a keyhole limpet (which it looks like it may be, but the photo is too grainy for me to tell you for certain), I don't know that anyone has actually confirmed that they eat SPS (much like how people believe "Asterinas" - actually Aquilonstra - stars might eat their corals: it might be a species specific thing, it might be a you have way too many starfish so they're out of other food options thing, it might be they're eating the slime coat/mucus on the coral rather than the coral itself, or they might just opportunistically eat unhealthy corals).

If it has a little "keyhole" or bullet hole looking hole on the back of it's shell (where the shell comes to a point) then it's a keyhole limpet.

Personally, I'd assume keyhole limpets are probably safe, but I know a lot of people would rather play it completely safe and not take the risk.

Fishy888 · Nov 16, 2022

Don’t believe everything a LFS tells you. They’re there to make sales. Those are limpets which are snails.

MaxM · Nov 16, 2022

I love limpets. I'm surprised you could get them off. They stick very tight.

Mikedawg · Nov 16, 2022

Looks like you also have a vermetid snail on one of the shells, bottom in first pic- is that what you were asking about?

homer1475 · Nov 16, 2022

Yeah could be the vermetid snail they were talking about being a worm. And they can become an issue.

Maybe they thought you knew the snails were limpets?

Scubapat · Nov 16, 2022

WheatToast said:
Looks like limpets, which are flat snails.

Thank you for the info!

Scubapat · Nov 16, 2022

Mikedawg said:
Looks like you also have a vermetid snail on one of the shells, bottom in first pic- is that what you were asking about?

Thank you for the reply, and your sharp eyes pointing out the possible Vermetid Snail. I read a bit about Vermetid Snails and if that’s what they are then I do have a real problem. I have not seen any mucus filaments which are said to be associated with Vermetid Snails. I am attaching another pic for your opinion. What are the spikes coming from the rock?