What are these starfish looking things in my son's nano?

[spankey]

I just set this tank up and today I noticed what apprears to me these little tiny star fish looking things all over his glass?

 

I did my best snapping pictures of them. Can anyone let me know what they are and are they harmfull? They must hitched with the live rock?

 

Thanks for your help and ID!

 

Spankey

 

 

[fishybusiness]

I heard those were a type of hydroid. They feed on

the little pods in your tank. The numbers in my tank

usually rise and fall with the numbers of pods. They

aren't really a problem for you unless you have seahorses.

[BKtomodachi]

Those arent a problemw with seahorses at all, actually.

 

But yes, they are hydroids, a very very small type. Harmless.