I've recently noticed my brown Xenia has long thin strands coming out of it during the day and night. It retracts in on occasions, but have seen it out majority of the time.

Anyone know what it is doing and whether it will harm any other corals(so far haven't noticed my mushroom having problems, and it touches it regularly)?

Thanks.

The non-branching corals sometimes have 'sweeper tentacles'. These are used to kill other corals (mostly branching ones) and clear out space for growth. These sweepers are usually retracted during the day.

If those tentacles are sweepers then yes, they will kill the polyps of neighbouring corals. Avoid placing branching corals too close to it.

P.S. I don't keep corals, this is just from biology lectures .

can you get a pic??????

xenia dont really have sweepers. are you sure its not something attacking the xenia?

I don't think Xenia have sweepers. Are there any soft corals that do? I don't think so.

I'll have another look and try to take a picture. These strands are very fine.

Thoughts of a newbie...

One of my leathers puts out very fine 'fishing lines' (like long piece of silk with small threads off it) - most often at night. (Don't say looking for fresh water! ) Anybody else has this? What are they/what do they 'do'?

Other corals can expel their zooxanthellae in strands - could Xenia?

I'm wondering if its headless xenia? or a tube worm on the rock next to the xenia? thats my guess

Rossco, I think those threads you're seeing are just shed slime off the leathers. Can look like threads.

No, had enough slime to recognise slime now!

These are definitely threadlike - got the old/new digital camera working better so will have to get a picture. It can put it out, sometimes two or three of them, about 5 to 6 cms within a few seconds and pull it in again just as quick.

In cloud terms it looks like a very long 'mares tail' !

Rossco, I think those threads you're seeing are just shed slime off the leathers. Can look like threads

no disagree, they are some sort of comensal (parasite?) flatworm living mostly on sacrophyton leathers. been looking in my books and magazine's because i have seen a picture with name in one of thembut of course can't find the bloody thing. i have also seen one on a xenia when i didn't have any leathers (supsitute host ?). they blend in perfect with the host they live on and are very hard to spot. at night they will extent very long sweepers, which are pretty cool to look at with a torch, they expand them and then retract them with a short time. the sweepers themselve look pretty cool too. it doesn't seem to do any damage to the coral it lives on and if you really don't like it then you can easely remove it with some tweezers. i would take it of you if chuck it away. they seem to be filder feeders of some sort.

i only ever had 3 of them and that of a long time of reef keeping. they seem to vanish after a while, may be just enough food

Cool...I think...well at least I'm not the only one just imagining them!

:lol:

well at least i am not the only one that looks into his tank with a torch in the middle of the night. always get funny looks when i mention it to other non - salties. :lol:

Had a really close look and the strands are coming from something else outside of the Xenia. Looks to be as Cookie said. Doesn't seem to be causing any harm to any of the corals at this stage so I'll leave it as is.

Thanks for the info Cookie! Well spotted.

Yup, bonus points to Cookie for observation.

On closer inspection the strands do come from underneath the leather. It initially gave the illusion of coming from the leather itself as it usually emerges from underneath one of the 'folds'.

Well that's interesting Cookie!

Always something new to learn!!

http://faculty.washington.edu/cemills/Ctenophores.html

ctenophore is what i was looking for.