Growth, sponge, or algae?

[Paul31733]

Hey everyone!
I was cleaning my tank when I noticed one of my acans has something growing around it.
Hopefully someone can educate me as to whether this is coral growth or a problem I need to address.
Thanks!
Paul.

 

[supernanoguy]

Hard to see what you are talking about.

 

[Paul31733]

Hard to see what you are talking about.

My green acan you can see the old looking skeleton on the sides.
The red one has some pinker looking stuff growing all around the outside and onto the plug... It does not look the same as my other acan skeletons.

 

[Paul31733]

 

[Nadine1]

I can see a sponge

 

[Paul31733]

I can see a sponge

Will it be ok or will it hurt my coral?

 

[samnaz]

Sponge. Harmless.