I still agree with BillyZ that these are possibly Vermetid snails. The ones I have had - the "stick" is not even as thick as a wooden matchstick. Very small and narrow.
The only time you might see them send a tentacle out to feed is when there is food in the water - they sometimes send out a filament/string to catch the food. If you have a few, it almost looks like cobwebs.
Here's another pic: