Is this a sponge?

[SonyaBAZ]

I noticed this growing on the base of two of my Zoa colonies. Is this a type of sponge? Should remove it or leave it? Kind of seems like it might overtake the colony. Thoughts?

 

[WV Reefer]

I noticed this growing on the base of two of my Zoa colonies. Is this a type of sponge? Should remove it or leave it? Kind of seems like it might overtake the colony. Thoughts?

Looks like sponge. If it’s a problem just tweeze or scrape it off. Some of them can be aggressive growers.

 

[sixty_reefer]

Give it some more light and the sponge will dissolved on its own