Help, what are these small stars?

[the mantis lover]

Please help identify these little guys, they look like a type of anemone, and are very small (1 mm big)
They formed a small cluster and there are individuals scattered around.
My tank has no coral but has some macro algaes, rock, 12 small clibanarius vittatus hermit crabs, some anemones of unown species, and 2 mantis shrimp.
will these be of any harm to the inhabitants?

I have shortened the list to a type of hydriod but haven't been able to go further than that.

These are the best images I could take of them.

 

[reaper93]

Little blurry but possibly hydroids?
Edit: should have finished reading your post where it says you already think it's a type of hydroid..oops

 

[blaxsun]

I can't tell, either - if you search for images of hydroids to they match what you see visually?

 

[Mastiffsrule]

EveNing,

The pics do make it a bit hard. I would guess Spirorbid worms. Non harmful but can be invasive. You can use a plastic scraper to manually remove them

 

[the mantis lover]

I found a pic that resembles it better, they are saying its a hydroid jellyfish. I don't know if they are harmful to my inhabitants tho.

 

[Rick's Reviews]

Spiriodworms don't have a pattern of growth, they just appear where best food intake is (ok some pattern).
this plate you have in your aquarium? This is a plate for corals but you say you have no corals in this aquriam.
I think the above mantis lover nailed it.... But why have this plate if no corals??

 

[Rick's Reviews]

Don't normally ask questions in regards to stuff but hate being tripped up over something so silly

 

[the mantis lover]

Spiriodworms don't have a pattern of growth, they just appear where best food intake is (ok some pattern).
this plate you have in your aquarium? This is a plate for corals but you say you have no corals in this aquriam.
I think the above mantis lover nailed it.... But why have this plate if no corals??

What plate? My tank doesn't have any. if your talking about the black thing that's a black pice of plastic I used as background to get the best pic I could