Anyone knows what this is?

[oki2oki]

Hi

On one of my rocks I am starting to see this. Anyone know what is this? Looks like someone or something is building a house or something. I have few anemones, clownfish and hermit crabs. Should I be worried about this?

Thanks A

 

[EeyoreIsMySpiritAnimal]

Are you talking about the sponge? If not, please be more specific.

 

[nkyreef]

The object in the middle of the picture is a sponge.

 

[oki2oki]

Are you talking about the sponge? If not, please be more specific.

Middle of picture. Seems like 2 ppl responded that it is a sponge. Thank you.

 

[oki2oki]

The object in the middle of the picture is a sponge.

Thank you.

 

[jabberwock]

Spongey Sponge Spongerton