Who is the Hitchiker here??

[auntkaren]

Yesterday we bought our 2nd coral at our local LFS. It's a small colony of green striped mushrooms. We were thrilled to notice a hitchiking white/green fan worm too. We got them home, placed them at the bottom of the tank and OMG the whole rock clamped! :scared: We aren't sure what kind of crustacean it is but it seems to be melded into the rock and opens only about 1/4 inch. So is the rock the hitchiker or the shroom and fan worm? What are our corals attached to? A clam? A muscle? An oyster? The rock is about 5 1/2 inches and the un-named critter is about 4 inches of that!
Here's a couple of pics check out the outline of the critter. :notsure:
Sheeesh!

 

[thomas712]

Perhaps a bivalve of some type, similar shape to a scallop or barnacle, not sure.

 

[auntkaren]

Well since we now have an unknown bivalve or whatever, how do we keep it from dying? Any suggestions on what to feed it? It only barely opens like 1/4 inch and the shrooms surrounding the "opening" are not disturbed so it seems to me that it filters plankton. We are not currently feeding store bought plankton and the tank is a 24G nano should we buy some to feed this thing?? :help:

 

[celacanthr]

Yeah, I am gonna say bivalve also, could be possible that the rock colony used to be a coral, and the coral colony then grew onto part of the bivalve, and then died.
Lots of phytoplankton may keep it alive.
HTH

 

[auntkaren]

I've got to go get some then. Any suggestions on which kind? How much should I give it it looks like it's about 4x3"