ID on pest on glass

[Mhamilton0911]

I found these stuck on my glass this morning, and idea what it could be?

 

[andiesreef]

medusa hydroids. should burn themselves out - how old is your tank?

 

[Mhamilton0911]

New tank. I'm 7-8 weeks in. Started with half live rock half dry base rock.

 

[andiesreef]

sounds like a good environment for these things then. they are relatively harmless.

more info:

Critter Identification: Hydroid Jellyfish – First Time Fish Keeper

f you are seeing tiny star-like organisms on your glass, they are likely to be Hydroid Jellyfish. They sort of look like very small Aptasia, or a snowflake or even baby star fish, they are not really much bigger than the head of a pin (1-2mm max).

firsttimemarinekeeper.com