I think there’s dead ones on my rock it looks like hollow little squiggles and it’s just about as hard as my rock isWhen open do they look something like this:
If so, feather duster worm. Beneficial filter feeder common in reef tanks. They spread a lot in new tanks then die off after a bit.
Other guess is vermetids, but you said they released a fan and were soft. Vermetids release a large mucus net and are hard as a rock.
Oh nice thank you! I believeThey look like colonial hydroids to me.
thank you very helpfulHydroids can spread and sting coral similar to aiptasia. The tube forming varieties can be a bit of a pain to get rid of. Your best bet is to dab some gel superglue on the ends of the tubes to smother them.