Anybody know what this is?

[TheRompe]

My tank has been set up and doing well for a little more than 5 months. I have some fish, LPS, SPS and softies... everything is thriving. Yesterday the attached pic below of the white round thing appeared. When lights went out it disappeared and then reappeared in the same spot this morning.

I'd greatly appreciate any insight as to what this might be. Also, friend or foe?

 

[TheRompe]

It's about 1/2 inch in diameter.

 

[Reef Jedi]

Interesting, I’m not sure what that is! Although may I suggest an emerald crab to help with the bubble algae. They are reef safe and will do a good job to eliminate it.

 

[musselman]

Looks like a crab shell.

 

[TheRompe]

Interesting, I’m not sure what that is! Although may I suggest an emerald crab to help with the bubble algae. They are reef safe and will do a good job to eliminate it.

thanks, added some emerald crabs a couple of weeks ago... they're slowly getting it don.

 

[TheRompe]

Looks like a crab shell.

that it does except it disappeared last night when the lights went out and reappeared this morning. It seems to be attached to the rock.

 

[BryanM]

Looks like a shell to me, wonder where it disappeared to :o

 

[TheRompe]

right where it is now

 

[Fish Fan]

This is the top carapace (shell) of likely an Emerald crab. This could be from a recent molt, and the crab may be hiding while his new shell hardens.

 

[TheRompe]

This is the top carapace (shell) of likely an Emerald crab. This could be from a recent molt, and the crab may be hiding while his new shell hardens.

Ok, that makes sense... thanks