Damn what is this now??

I guess looking at my tank because i was bored and after examining it closely ive always though that sand particles were on the rock (i have white sand) closer inspection i see little swirl like things growing all over my rocks. one rock is covered in it and the rest have like 3 or 4 here and there what are these things? they are white and look like little swirls.

 

Serpulidae, they can be found near the bottom/end of the link.


Worm Hitch Hikers

 

Yeppers...Spirorbid fanworms. If you look closely, you can see the little red tufts of their gills sticking out of the shell.

 

are they bad to have?

 

I wouldn't worry about it. I used to have a ton, and now they're pretty much gone.

 

No they are not.