Is this a sponge?

Hoisted · Dec 25, 2023

Hello, is this a sponge? It's white growing on my rock. I was able to break a small chunk of it off with my turkey baster and smash it. It feels spongey? It has no smell and did not crumble. Can anyone help me figure out what it is? It's growing on the bottom side of my colony of zoas, idk if I should remove it entirely or let it be? Seems like it may suffocate my zoas.

Thanks in advance!

Reefkeepers Archive · Dec 25, 2023

Sponge, completely harmless, they usually die back over time. Also those are palythoa, not zoas.

malfist · Dec 25, 2023

Sponge, leave it be, it won't harm anything. They like to grow in low light moderate flow areas. They're a filter feeder and can be beneficial.

The only risk is if they grow over a coal, which is highly unlikely to happen

kevgib67 · Dec 25, 2023

Good filter feeder but for some reason you can remove the rock put it in a container of tank water and scrub it off with a toothbrush.

Reefer Reboot · Dec 25, 2023

kevgib67 said:
Good filter feeder but for some reason you can remove the rock put it in a container of tank water and scrub it off with a toothbrush.

But before you do that you may want to research Palythoa Toxins just to be on the safe side.

Reefkeepers Archive · Dec 25, 2023

kevgib67 said:
Good filter feeder but for some reason you can remove the rock put it in a container of tank water and scrub it off with a toothbrush.

I've had this exact sponge grow on the stems of my zoas, all the way up to the crown. didn't harm anything and died back in a few weeks.

kevgib67 · Dec 25, 2023

Reefer Reboot said:
But before you do that you may want to research Palythoa Toxins just to be on the safe side.

Good catch, I didn’t think about the palys.

kevgib67 · Dec 25, 2023

Reefkeepers Archive said:
I've had this exact sponge grow on the stems of my zoas, all the way up to the crown. didn't harm anything and died back in a few weeks.

Ya, I’d leave it myself but if OP doesn’t like the the look or that rare occasion it did start smothering coral I was just offering an option on removal.