Massive Vermetid snails that haven't spread?

[Sharlow]

I've circled the guys I'm trying to I.D.. They came on an Euphyllia skeleton that had been sitting in a 10+ year old tank, and has been in my pest tank for 18+ months now. They look like common Vermetid snails, except they're huge. The operculum is roughly 6mm across, and I've seen these guys stretch out of their tubes about an inch. I've seen them throw little nets, but they don't seem to irritate anything. They also don't spread or reproduce. Despite being in my tank for almost two years, there aren't any new ones, or any classic Vermetid snails. Ignore the old tubes above them, they're long dead.

 

[lapin]

Kewl

 

[Sharlow]

They're really neat, I just wish I knew what they were.

 

[OlderManSea]

I've circled the guys I'm trying to I.D.. They came on an Euphyllia skeleton that had been sitting in a 10+ year old tank, and has been in my pest tank for 18+ months now. They look like common Vermetid snails, except they're huge. The operculum is roughly 6mm across, and I've seen these guys stretch out of their tubes about an inch. I've seen them throw little nets, but they don't seem to irritate anything. They also don't spread or reproduce. Despite being in my tank for almost two years, there aren't any new ones, or any classic Vermetid snails. Ignore the old tubes above them, they're long dead.

I have a few of those. Mine do spread slowly. They don’t irritate the corals much but they ignore me horribly.

 

[king aiptasia]

5+ mm is not unheard of for vermetid snails, curious specimen you got, are you able to get a more crisp image? Not sure about specific species, but there are quite a few fossil and modern vermetids bigger than 5 mm

 

[Sharlow]

Tried to get a couple photos or videos from my phone, but I'm not having my luck getting it to focus. You can see the tube length in the first picture, it's 4 or 5 inches long, and looks like my large feather duster tubes.

 

[king aiptasia]

Tried to get a couple photos or videos from my phone, but I'm not having my luck getting it to focus. You can see the tube length in the first picture, it's 4 or 5 inches long, and looks like my large feather duster tubes.

In my unexpert opinion it is in the genus Vermetus. A fairly ancient lineage of snails and once a more major reef building animal

 

[king aiptasia]

Honestly im kinda jealous of this unique aquarium find, not so often you find these huge specimens