I have Scarlet hermit crabs and they leave my snails alone. But they do need spare shells when upsizing is required.
Wish I had seen your posts about Aiptasia before you put your worms into your DT ...
In 1 instance a had a 4-5lb hunk of LR that I placed in a bucket with no cover. Over the next 1-2 days I found aiptasia crawling up the sides of the bucket.
In the other instance, I was selling a RBTA on a rock and the buyer was delayed, so I placed the dude in a critter keeper in my sump. Overnight the 'nem crawled off the rock and found the highest point inside the container it could reach.
I'm sure 'nems walk around looking for ideal lighting and flow
Maybe next time, if you ever deal with them again, you could consider putting whatever you have in a low/no flow environment with only light from above ...
Thanks for sharing the article about QT'ing inverts. I'll definitely be reading up on that over the holiday.
Also picked up a bottle of vibrant, going to give it whirl on GHA. Are you getting any results with it yet?
Had the same problem with a hermit crab in my nano tank. Literally saw him yanking or tugging on the snail for dear life trying to rip it out of the shell.. Despite having multiple empty shells of various sizes to choose from. I plucked that guy out the instant I saw that and dropped him into my other tank where there's no snails. Little jerks!