Spider in reef tank?

[steve64]

Hi, something in a corner of a rock in my reef tank is sending out what looks like a spider web material..It's coming from tiny black nub or hole...Any Ideas/ experiences with this? Is this dangerous?
beneficial?..................Ty Steve

 

[jfdjason]

Spiderman???

 

[lovethesea]

peanut worm maybe?
harmless do a search here to see if any pics.

 

[yellowtail]

do you have a sixlined wrasse?

 

[ophiura]

I suspect it might be a vermetid snail, which secretes mucus strands to catch food - into the water column. Very evident usually if you clean the tank so that there are pariculates floating around that get caught up in it. However, is it strands on the rocks? Then it might be something like a spaghetti worm. Both are harlmess....speghetti worms are beneficial IMO but vermetids are just kind of there. They aren't an issue though sometimes can grow in pipes and hoses obstructing flow. But this is a pretty extreme situation.