Anyone know what it is

[djflashback83]

been growing on this piece of rubble coral in the refugium

 

[nvdiz]

looks like some kind of sponge

 

[lunacris]

you killed sponge BOB !! HAHA . Looks like yellow sponge. ive had it never a problem

 

[jm23]

Sponge. A keeper.

 

[djflashback83]

Nice thought so just discount double checkin lol