what are these?

[llama72]

I have noticed that i have at least 50 little black things growing on my coral that look like a snail's snorkel. If i turn my pump off and the water isn't moving very much, that shoot out a web-like substance. Does anyone know what these are? Are they harmful or beneficial? Should I try to get rid of them?

I will try to get a pic too.

 

[Hormigaquatica]

Do a search for Vermetid Snails- see if those are the critters youre looking at.

 

[Deleted member 143833]

There are a few critters that fit the description here, including a good image of a Vermitid snail:

http://www.xtalworld.com/Aquarium/hitchfaq.htm

 

[llama72]

that is exactly what they are. Thank you for the help!!!!