White fluff growing out of liverock

[pinocchio]

Is this just algae? Kind of looks like a cotton swab

 

[SlugSnorter]

Is this just algae? Kind of looks like a cotton swab

perhaps a sponge

 

[pinocchio]

Worth keeping or should I remove?

 

[vetteguy53081]

Worth keeping or should I remove?

Its poriferan sponge and will spread but slowly. While harmless I often remove it with a dental pick Or you can inject with vinegar and it will shrink

 

[SlugSnorter]

Worth keeping or should I remove?

As with what Vette guy said, its not really gonna harm anything, and will filter feed nutrients from the water. I would say to keep it, and cut it back if it gets too big for your liking