Is this some sort of hydroid?

[Speg]

Hard to take a picture because they're so thin... I thought it was some type of macroalgae that was growing, but I messed with one today and it retracted..

They're about an inch or two long....very slim...almost looks like short feathers that come off of the long part...moves like hair algae but white in color.

any thoughts? I looked at several pics of hydroids but couldn't find something similar... maybe some type of worm?

 

[gflat65]

That's what it sounds like. As tanks mature, it's not uncommon to see forests of little calcarous tubes with little white or red fanned feather duster like worms. Usually in lower flow areas.

 

[Wy Renegade]

Yep, if they're retracting I would agree with feather duster worms, the small ones.

 

[Speg]

I don't see any sort of tubes whatsoever...in fact, that's why I thought it was some sort of algae because it looks to just be attached right to the rock..no hole or nothing.

 

[Wy Renegade]

Interesting; tube worms have tubes, I believe that hydroids don't retract (although it may depending on the type), the only other option I can think of would be nuisance nems like manjo or aiptasia.

 

[Speg]

Doesn't look like an anemone at all..it's very long and thin...like a single strand of hair but with little "feathers" or additional hairs that go up the length of it..and they range from 1-2 inches long....I'll try to draw a pic.

 

[CJO]

There are hydroids that retract. However, the ones I've seen look a lot like miniature aiptasia, they don't have the fronds on them that the feather dusters do.

CJ