Feather duster ID/Question

[Menace2Sobriety]

Found these dusters on a recently acquired chunk of live rock. Until now I've only ever seen the lighter "tan" with darker "reddish-brown" spots. These orange ones are new to me...

Are the hitchiker dusters all basically the same? Is there any notable differences between them? Or are they simply all just filter feeding hikers with no real way of differentiating between them other than color?

These ones don't seem to have long squiggly tubes like the other ones I have... these seem to come from a stubby "mound" of "shell/calcium".

Are any better than the next? These ones are on a VERY high end piece of live rock.... probably a 15 lb piece that's full of caves, corraline, etc. and is about the size of a soccer ball.

The "feathers" also seem shorter and fatter compared to my other duster hikers. At first I thought they were aptaisia until I enlarged the photo (because they're so small) at which time I noticed the "feathers".

Not only do these have "feathers"... they also seem to have "spikes" that stick out. The odd looking "spikes/hairs" is making me wonder if they're bad for corals (will they sting?).

Thx.

Menace

 

[Betta132]

I think you just have fat dusters. They're harmless, those aren't real spines. If it lives in a tube and sticks feathers out, it's a filter-feeder and won't hurt anything.
To my knowledge, there's no real difference between various hitchhiker dusters, aside from size difference.
A LFS near me has some brown hitchhiker type dusters almost 3" long in the filter compartment of one of their display tanks, and those are about the biggest hitchhiker dusters I've ever seen.
Yours are neat! I'd try and feed them, try to get them to spread a bit so you can see more.

 

[Sky_Shark]

Those are really cool little feather dusters. I'd buy a rock with them. Great color. Consider them a lucky hitchhiker

 

[Mael]

The feathers are actually the gills of the worm. I have some tiny red ones that hitch hiked on some LR and some little white ones as well, they wont do any harm and look pretty neat.