Clear/White stringy stuff on rocks

[bobmakespancakes]

i just added rocks today and now i am seeing this stuff it may have been there before but i am not sure does anyone know what this is?

 

[biophilia]

It's hard to tell from the photo, but given that you said they're new rocks, I'd be willing to bet they're colonial hydroids. If you do nothing and just ignore them they'll be gone within a few weeks at most.

 

[samnaz]

I agree hard to tell but I’m guessing hydroids.