IDs please

[adurost]

1st pic: I have had some of the most interesting creatures take up residence in this dead piece of coral! Last night I saw this little guy for the first time... Any ideas what kind of urchin it is and if I need to be concerned about keeping it in the tank?
2nd pic: Any ideas what the filamentous white stuff on the LR could be? It is growing in several locations in the tank.
Thanks!

 

[spanko]

2nd picture is sponge now worries there.
1st picture hare to tell what kind of urchin it is.

 

[sharkbait35]

1st pic- Maybe its a Black sea urchin.

 

[adurost]

Originally Posted by sharkBait35
http:///forum/post/3117540
1st pic- Maybe its a Black sea urchin.

They are very common here in hawaiian waters, and my LR and feather duster were 'local' purchases. So it's the moonlights that made it look green?

 

[sharkbait35]

Originally Posted by adurost
http:///forum/post/3117558
They are very common here in hawaiian waters, and my LR and feather duster were 'local' purchases. So it's the moonlights that made it look green?
What color is it? Does it have white rings at the base of the spines?

 

[ophiura]

I think the second is an arborescent foraminiferan, but it depends on the scale of your photo.
Hard to tell on the urchin. He's quite pretty. Where is your rock from? Probably a species of Echinometra.

 

[adurost]

Originally Posted by sharkBait35
http:///forum/post/3117561
What color is it? Does it have white rings at the base of the spines?
Not that I can tell. The spines look black during the day, but it is small (about 1/2") and it hides in that coral bone during the day so that it is difficult to get a close look. I've seen it out like that only twice at night.
Originally Posted by ophiura
http:///forum/post/3119352
Hard to tell on the urchin. He's quite pretty. Where is your rock from? Probably a species of Echinometra.
Molokai'i LR... the only kind you can legally purchase here in Hawaii!! It is DIY rock that the guy has a permit to allow to grow in a 'fish pond' and sell.
Originally Posted by ophiura
http:///forum/post/3119352
I think the second is an arborescent foraminiferan, but it depends on the scale of your photo.
It's less than 1/2". I posted the pic with the zebra hermit crab (in the black nerite shell) to try and give a visual reference. It's gone now... I think the narcissus snails ate it.

 

[ophiura]

Ah, well it is likely Echinometra matheai....(I wanted to attach a picture from my trip but it is acting up ) Maybe later.