what is this?

[armywife1314]

once again more surprises arising from the rockwork of my tank. what is it? its been growing very very slowly but it is getting bigger.

any help is appreciated. thank you

 

[bang guy]

It's a Vermitid Snail. They reel out strings of sticky mucus that traps plankton and detritus and then reel it back in to eat it.

 

[morval]

+1
bang guy knows his worms