digitate hydroids?
 

I have noticed that my sun polyps have been looking a little sick lately so I moved them to a different spot in my tank, and when looking in my tank tonight I noticed I have digitate hydroids on my LR where the polyps were sitting. I googled them and am 95% sure that is what they are. Anyone know what I need to do to remove these guys. They look like a 1-2 inch long piece of thread/feather looking thing that is coming out of small holes in the LR only at night.

Are they solitary or are there a number of worms in each hole? If there are a lot of worms colonizing a shared hole, it may be a spaghetti polychaete worm. I have never heard of digitate hydroids being parasitic. They are reef-safe filter feeders to my knowledge.

Digitate hydroids sway and retract when they collect food, while spaghetti worms creep around, stretching out in all directions and retract in the same fashion.

Ya they are solitary strands coming from my live rock. I have a another rock with spaghetti worms on it, so I know what those look like and its definitely not them. I thought hydroids could sting neighbouring corals.

Hydroids can pack quite a sting, I don't know about the digitate ones but I had the myrionema (sp) ones and another kind (perhaps digitate, I haven't googled them). One did some damage and the other was "ok" (things were unhappy around them but no damage). I've tried yanking them out (their tubes are quite tough and they have anchors deep in the rock, even if you do manage to yank them out often the "root" is left and they just regrow. I've also epoxied over them. I've found you have to be really generous with the epoxy in both thickness and spread, they seem to worm right through it if it is too thin, or around it if you haven't covered enough area. The only true success I had was with taking the rock out and hammer/chisel the affected chunk right off the rock.

Good luck!

I have a few of these here and there in my tank... I have noted that when the 'stingers' or whatever are dragged across my zoas, they don't seem to do any damage (or even bother the zoas). I don't have any SPS or LPS at the moment though, so I can't say if they would be bothered by them.

Are digitate hydroids much of a threat? Or do they just irritate corals? I have a few of the normal type and I know for sure that zoas don't like being within a half inch of those.

How old is your tank? I have searched both on here and RC looking at old threads on these guys. From what I read they tend to go away in time. They will let go of the rock to go to another spot as well and there was one suggestion to filter the water to catch them as they release. I have a lot of them in my tank right now and it is a new tank. My Zoa has not seemed to be bothered by them yet. I am hoping to give it a year and let them die off naturally.

Palmer