I just got some small rubble live rock from my LFS an the once piece has what appears to be long clear tentacles reaching out from it! after doing some google image searches I believe it to be Vermetid Worm Snail? Is this bad for my tank???
I am new to this myself but from what I understand some hitchikers or critters are good for the tank. Are you sure its not a bridle star? If it is those are harmless and are essentially starfish. Just trying to help you out, like I said im new to this as well. Google and so some searching. Hope this helps.
if your are unsure of the critter inside your tank the best thing to do is simply to remove it. a lot of times bad critters can be mistaken for good ones. never worth the risk in my opinion
I wouldn't really classify a vermetid snail as a 'worm' The tentacles they throw out are more like threads than a worm.
Is there any chance of posting a pic?
If it is a vermetid snail - they are fine as long as you don't have a ton of them. They eat particles from the water column.