What is it????

[hillegom]

Get a 10X loupe from someplace like princess auto. Or just any magnifier glass
You will be able to identifier it easier

[monocus]

if they are soft it could be aptasia-i have a lot of white dots, but they are hard ,in my sump-i don't think they are a feather duster-though i do have hundreds of spaghetti worms in the sump

[imcosmokramer]

pods

[kenman999]

Thx for the replies. I don't think it is the white star. I have roughly about 200 white dots. They look like little spiders. It has a solid white center which is pretty much a circle shape doesn't look like pods to me either.

[Aquaria]

Sounds like hydroid jellyfish kinda. how old is the tank?

[gobytron]

I would bet they are tunicates or sponges...

[kenman999]

It Looks exactly like hydroid jellyfish!!!! The tank is set up for a few months but all my live rocks and sand were transfer from a 3 years old tank.

Is it harmful should I remove them?