Feelers - Any Ideas...(?)

[Thane]

So my 45 liter (12 gallon I think) tank has been doing really well. Been going for 3 weeks now and the nitrates and nitrites and amonia level are almost non-existent... so I'm really happy about that but now for my question. I got live rock, and I noticed "feelers" on the one rock, thought cool... I have life in my tank something to look at... well, now I'm curious as to what they can be. The come out of a tiny tube, can't be more than 1 - 2mm wide, the are very fine and long... any ideas? I now have 3 one the one rock and 1 on another... I'm just wondering what it could be... Would try and take a pic, but way to small... Thanks in advance