Tiny round critter thing with flagella or something all around the perimeter of its body… please help ID

[katforscience]

My tank in the last few days has been getting these tiny tan-brown ish circular creatures on the glass… they don’t really move, just sit there with their appendages or whatever flowing in the current… are they harmful? Does anyone know what they are? I can’t find anything and don’t even know what category to look under… they are big enough to see with the eye but quite tiny… tank is a 40gal with life rock, live sand, and I have a HOB refugium with some sea lettuce, some branching rock, and a bunch of copepods… as well as a bunch of gha growing in there right now and prolly some diatoms… but yeah, I don’t see these creatures in my refugium, I’ve only seen them in the display. I didn’t have a good way to magnify them but I hope the pictures are okay enough! Thanks for the help

 

[Mr_Knightley]

Sounds like solitary hydroids based on your description. Are they shaped like cones with the tentacles around the wide end?

 

[katforscience]

Sounds like solitary hydroids based on your description. Are they shaped like cones with the tentacles around the wide end?

They look more circular in shape and the tentacle things span the entire perimeter of their body

 

[katforscience]

Here is a couple more pictures including one with my pinky finger for size comparison

 

[Mr_Knightley]

Could still be hydroids, or possibly larval aiptasia anemones.

 

[katforscience]

Could still be hydroids, or possibly larval aiptasia anemones.

Don’t love that lol I wonder how I managed to get those

 

[EeyoreIsMySpiritAnimal]

Don’t love that lol I wonder how I managed to get those

Your tank is still young. They are hydroids and will go away on their own.

 

[katforscience]

Your tank is still young. They are hydroids and will go away on their own.

Thanks!! every little thing in my tank has me paranoid lol

 

[EeyoreIsMySpiritAnimal]

Thanks!! every little thing in my tank has me paranoid lol

Just enjoy the diversity

 

[Tavero]

Jellyfish.
They will starve in a few days

 

[katforscience]

Thanks guys I feel a lot better about them