White cocoon sack ID @ (pictures)

[dawgface]

I have what I can only describe as a white cocoon sack like thing showing up throughout my tank. I noticed one a few days ago and now today I've spotted atleast 6 throughout the rock crevices. Hopefully you guys can lend me your expirence here for identification.

FWIW I have the following animals in the tank
Regal Tang
Sailfin Tang
Cleaner Wrasse
2 Clowns
Lawnmower Blen
Pistol Shrimp
Yellow Watchmen
Couple emerald Crabs
Anemone Crab
Coral Banded Shrimp
nass. Snails
Red and Blue leg. Crabs

Heres the pictures


Look closely between the Tonga.
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[jdabs]

+1 on the sponge!

 

[insane_reef_keeper]

I have those in my tank as well, they open up like a tube worm and close up the same.

 

[mapleredta]

Yup, those are sponges.

 

[gnashty]

kinda looks like a pineapple sponge, great filter feeder.

I used to get a ton growing in my overflows