Something growing under my zoas… sponge? ID help please

[Les Poissons]

I was on vacation for 10 days and came back to find this growing under my zoas. Some sort of sponge maybe? Good…bad…neutral? Doesn’t seem to be bothering them at this point and was probably growing there before I left, but I didn’t see it before when it was smaller. ID help would be appreciated. Thanks!

 

[JaimeAdams]

That is a sponge. I would suggest pulling it out and hitting it with some hydrogen peroxide.

 

[reddevilant]

Yeah, definitely a sponge. I have the same thing growing in some of the crevices of my rocks. Good filter feeder and technically harmless but, this species is an aggressive grower IME and could possibly smother the zoas.

 

[Projects with Sam]

nice photo!