What is this thing?

[RobertK]

Found this recently on some live rock from the Florida keys I bought last month. It is about 1" in diameter. When disturbed it quickly and completely retracted into (or under) the rock. Can't tell if it some sort of tube worm or anemone? I have 3 books about reef invertebrates but couldn't find it in any of them.

 

[rayadog]

Looks really cool though. Do you have any other picture perspectives? It looks like it’s got a skirt of tentacles.

 

[kevgib67]

An rfa?

 

[StartingATank]

It is interesting. I am also thinking either a mushroom or an anemone of some sort

 

[RabidDragon]

Anemones commonmly dig into the substrate with their foot and then retract under the substrate when disturbed. My rock flowers do this easily, that would be my guess.

 

[Mebbid]

Daisy anenome or Cereus pedunculatus

 

[RobertK]

Thanks for all the replies!

An rfa?

Does an RFA retract completely when disturbed?

Daisy anenome or Cereus pedunculatus

Is Cereus pedunculatus found in Florida waters? I looked it up and it said it is found mostly around England.

Will try to get some more pics today.

 

[Tahoe61]

https://scuba.spanglers.com/marine-life/caribbean/anemones
^ I believe your anemone can be found on this link.

 

[kevgib67]

Thanks for all the replies!

Does an RFA retract completely when disturbed?

Is Cereus pedunculatus found in Florida waters? I looked it up and it said it is found mostly around England.

Will try to get some more pics today.

Mine fold into itself creating a fleshy ball but not retract into the rock like you described, that through me off but it looks right. rock flower anemones are found in the Caribbean.

 

[RobertK]

https://scuba.spanglers.com/marine-life/caribbean/anemones
^ I believe your anemone can be found on this link.

Thanks for the link. I think my specimen most closely resembles what is called a sponge anemone in that link, however it has shorter tentacles than what others are calling sponge anemones in this thread (I did not buy my rocks from TBS):

https://www.reef2reef.com/threads/y...-anemone-on-tampa-bay-saltwater-rock.1081029/
It is on a stalk not in a tube. It retracts into a hole in the rock when disturbed. Some kind of a nem for sure.

Here are some more pics (taken with DSLR instead of cell phone!):

 

[rayadog]

It is really nice looking, hope it’s a friend and you can keep it alive.

 

[RobertK]

It is really nice looking, hope it’s a friend and you can keep it alive.

Thanks, me too! Its on a nice looking rock that has lots of sponges, coralline and macroalgae.

 

[UncommonSense]

Thanks, me too! Its on a nice looking rock that has lots of sponges, coralline and macroalgae.

I looked at this thing in-person today, it’s Definitely not a Majano, though it doesn’t quite match any anemone I’ve ever seen…

Rock flower Anemone would be the closest match, but the numerous tiny tentacles don’t really look “ruffled”… it also does not fluoresce under heavy blues from a Kessil A360X… perhaps it’s something not seen as often?

Does anyone have further ideas what this thing might be? — it’s very pretty up close!

 

[rayadog]

Hope you don’t mind taking a look @thamnasteroid

 

[rayadog]

It would be kinda novel to discover a new pest. Oh, to be ground zero. What a legend. JK it’s too pretty to be damning.

 

[thamnasteroid]

Some sorta nem, not sure what kind. Given that it's hitchhiking on live rock from the gulf, it's likely some Caribbean species.