Clam?

[jsmkmavity]

It almost looks like a scallop that has been encrusted with coral and other things.

 

[twentyleagues]

Yeah, this thing is very unusually large; the only species I'm aware of that I've seen even close to this size (and it's still smaller) with the spines is Spondylus rotundatus, which is extinct. Because of that, I'm assuming (if the top part is in fact part of the shell and not something else like a foraminferan, coral, hydrocoral, etc.) it's one of the other Spondylus species that I'm not familiar with (there are several dozen species and I'm only familiar with a handful at this point), but I could very well be wrong.

It's definitely an oddball critter, and I'm sorry it seems to be on death's door.

To me it looks like the top "frilly" stuff is something that grew on it. Also to me it looks like the white part inside the shell would be the muscle inside and typically you would not see that much of it the reason I said it was dying. If it is stuff growing on it that would make the animal more common and likelier possibility. I too have been wrong before and will be again!

 

[BryanM]

It almost looks like a scallop that has been encrusted with coral and other things.

I think it probably was a scallop actually. The muscle looked exactly like a scallop.

 

[twentyleagues]

I think it probably was a scallop actually. The muscle looked exactly like a scallop.

I am not a proponent of live or dry rock. They both have advantages and disadvantages. With LR you get things like this that are really cool but unfortunately most of the time we cant sustain them especially in a new tank. Or they die in shipping. Its unfortunate. Now that isnt always the case. Back in the day I got a couple good sized chunks of LR shipped in dont remember where from I think maybe fiji, but I had multiple bivalves, seasquirts, sponges and macro on them and quite a few lived for 2-3 years. At the time I was helping at a new lfs part time and did the wednesday import 5am run to the airport with the manager. I kind of got to pick and choose through the new import stuff, I got lucky with the picks I chose as a lot of the cool stuff on those rocks died fairly quick in the shop. I also was lucky in the fact I didnt get any of the nasty things that I saw emerge from some of the rocks in the next few weeks.

 

[ISpeakForTheSeas]

To me it looks like the top "frilly" stuff is something that grew on it. Also to me it looks like the white part inside the shell would be the muscle inside and typically you would not see that much of it the reason I said it was dying. If it is stuff growing on it that would make the animal more common and likelier possibility. I too have been wrong before and will be again!

I agree that it's probably something else growing on the shell, I'm just not sure what.