spider webs

[munchkin]

I keep finding what looks like spider or cob webs on one of the rocks in my tank. I have finally spotted what looks like 2 white antannae sticking out of a hollow barnacle looking thing. It looks like the antannae on a snail. They retract when any thing gets close to them. Anyone know what this might be and if it's harmful? I can't get an angle on it to take a picture.

 

[smoothie]

Vermatid snail. Not harmful. They just multiply like crazy and bug whatever their mucus string touches. Crush that one if you can or paste over it. Keeping prestine water can starve them out too.

 

[munchkin]

Thanks, I can crush it. It tokk me a while to find it.

 

[smoothie]

Be sure you crush the snail itself too. Free fish food