ID please - green round thing with little tube

[zielit]

Somehow I didn't noticed these before but I doubt they would appear suddenly and in a matter of day or two. I can find 10-15 of them already spread across the rock either singular or in group like on second picture. So far I haven't see anything sticking out that little tube either during the day or night.

 

[LAReefer4Life]

sponge.. possibly pineapple sponge

 

[fishguy242]

hi, sponge/tunicate...
@Mibu @Erin1971Texas may know to id both...

 

[EeyoreIsMySpiritAnimal]

Sponge. Very common. Not a pineapple sponge though. Good sign that your tank is doing well.

 

[WheatToast]

sponge.. possibly pineapple sponge

Not a pineapple sponge (Sycon sp.), but still a sponge. This one may be a “yellow sponge” (photo 1) or a “longhorn sponge” (photo 2). All of these are harmless filter-feeders.

 

[zielit]

Thanks guys for quick response, it is more or less established tank (2.5 years). So I was surprised to see something new, especially that I haven't bring anything new recently other than bringing chocolate chip starfish for my harlequins every week or two. But I need to admin that I've been busy recently and water quality might have drop a little bit as well, haven't check parameters in a while.

 

[Emanuel Refer]

Hi! I think that it may be a Clathrina.sp. The big opening like a tube is the oscula of the sponge. The oscula is the part of a sponge that acts as a exhaust hole. Usually the interior of the oscula is lined with a bunch of small cells that are called: collar cells. This cells have a little flagelum that moves water through the sponge’s body ( water enters the sponge from tiny holes on the outside of the sponge that are called ostia ) and besides the flagellum the collar cells have a little net like ring that traps food particles. Then the water without food particles exists the sponge through the oscula. If you are interested in more informations about sponges and cryptic zones look for: CMAT (volume 1 and 2) by Steve Tyree on reef farmers.com .
Best regards!