Okay what is this?

[BIGJ67]

HI GUY / GALS
HAPPY MOTHERS DAY TO THE LADIES!

Anyway, its been a lifetime since i posted.
Im now back in the game and everything has changed all new rules so im playing catch up, thank god gor the internet.

So last week i was moving thing arround in a 4 mth old tank when i noticed the happy stoway..
Mind you i started this tank with dry marco rock.. live sand, RO Water and i dip everything ! Except my clams.
Can anyone identify this ?
Is it friend or foe?
Its has multiple valves, 4 , its spongy with no reaction when touched.
What is it?

Ahh the video is too long to post
Sorry the photo is good tho.

Thank in advance!

 

[SuRFeR BoY]

Sponge. Usually means your reef is doing good

 

[BIGJ67]

Sponge. Usually means your reef is doing good

Wow, finally good news!
Thanx, think it came in with a clam?

 

[Josh]

It's a sponge, very good for your tank.

 

[Timfish]

What they said! There are a couple species of photosynthetic sponge that are invasive and do very well under bright lights need to be avoided. Most and especially the cryptic sponges we find under rocks are essential recyclers and process labile DOC 1000X faster than the bacterioplankton in the water.