Urgent Please ID

Please tell me what these hitchhiker things on my Coraline covered lr. They are the light blue little star looking forms.

 

Asternia Starfish and they are probably dinning on your coralline.

 

+1 I've heard the blue types are worse than the white.

 

The blue seems to come from dining on coralline algae. They do bear watching though to be safe.

 

+1 Asternia: They multiply by splitting. they do not grow large. they average 6 to 8 points but can be as few as 4.
In a well maintained tank they are pretty much harmless and numbers stay small but some people really hate these buggers. They will dine on some corals but in general your loses will go un noticed unless you have a huge outbreak.
I've actually bought some of these because friends think they are starfish and like to look at them but a star fis is NEVER getting added to my tank. I purchased 5 a couple years ago and never see more then 4 at a time but i am sure i have in the neigborhood of 30.
All of mine were white when purchased but they are all blue now.