What are these white spots?

[DadE02]

Does anyone know why my rocks and corals have white spots over the last week's weeks?


I have found the same spots on the shells of our hermit crabs, but our fish seems to be good.

 

[Sniperhank]

Do they move? It looks like pods or something, but really hard to see.

 

[DadE02]

No, they are fixed. I have attached a closer look at them

 

[Sniperhank]

Look like the shells of small filter feeding tube worms. Totally harmless and will most likely die off. Oh, and an emerald crab of course saying hello.