Any idea what these tree things are

[Lightspeed]

I have 2 of these things, one is cream coloured and much smaller, this one pictured is black.
I thought maybe cucumbers or apples but are not, they stay in the rock, the same rock since the display was filled with LR on the day of install, every week or so they extend these tree things for feeding, the branches of these tree things are retracted to the mouth a few times per minute to collect the food they have caught from the water column.
They came in as hitch hikers in my Live rock and somehow managed to survive my cycle which was very harsh, sorry bout the mobile pic under blues so used flash.

One pic is deliberately over exposed to try to show the outline in more detail

 

[JGT]

I have 2 of these things, one is cream coloured and much smaller, this one pictured is black.
They came in as hitch hikers in my Live rock and somehow managed to survive my cycle whic

Pics?

 

[Maritimer]

They almost look like the tentacles of a sea-cucumber ... Do they ever move, or do they remain upright and open at all times?

Some sea-cucumbers browse over the sandbed, ingesting organic material, and other species raise their tentacles into the water column to strain plankton from the water.

~B.

 

[JGT]

Pics are terrible. Can’t see anything,

 

[Lightspeed]

They almost look like the tentacles of a sea-cucumber ... Do they ever move, or do they remain upright and open at all times?

Some sea-cucumbers browse over the sandbed, ingesting organic material, and other species raise their tentacles into the water column to strain plankton from the water.

~B.

no they never move, always inside that rock, have never climbed over substrate or any of the rock work. Both only put out feeding tentacles once a week sometimes longer between shows, the diameter of the Black tentacles or feeders are over 10cm diameter and maybe a little longer in height, they are definitely feeding and seem to love the phyto i dose.
My aquarium service guy says he does not think they are cucumbers and is a bit mystified himself, anyway don't seem to be doing any harm and are very hardy after surviving my extreme cycle.

 

[taricha]

They almost look like the tentacles of a sea-cucumber

agree

 

[taricha]

the diameter of the Black tentacles or feeders are over 10cm diameter and maybe a little longer in height, they are definitely feeding and seem to love the phyto i dose.

could be something like this...
https://www.whatsthatfish.com/fish/magnum-sea-cucumber/1764

you can find other people who found sea cukes in their live rock...
http://www.wetwebmedia.com/cukeidf3.htm

Since it doesn't move it'll probably need a pretty good amount of food provided. Look up feeding for Sea Apples. might give you ideas for amounts of phyto etc.

 

[jesspal]

Look like gorgonians

 

[Lightspeed]

could be something like this...
https://www.whatsthatfish.com/fish/magnum-sea-cucumber/1764

you can find other people who found sea cukes in their live rock...
http://www.wetwebmedia.com/cukeidf3.htm

Since it doesn't move it'll probably need a pretty good amount of food provided. Look up feeding for Sea Apples. might give you ideas for amounts of phyto etc.

Thankyou sooo much @taricha.
I have done research on these critters far before i posted here, they looked so much like Cukes but i could not find any that had such large feeders, a few days ago i was looking at the Hellfire Anemone as these also shared similarities, but kind of did not exactly fit.

I had not read of Rock Cucumbers till your link in your post and that's about as close a match as i have seen in pics and habit.
So there you go, i learned something new today.

@taricha I know my pics were not great, its hard with my phone to focus 2ft into the tank at the back, the more you zoom on my Galaxy note 9 it seems the more detail i lose even using pro camera, thanks for not chewing me up about the pics, cant afford a 105mm micro lens for my Nikon dslr, i keep spending my money on coral.

Case closed, thanks to R2R;Happy