What is this, coral?

[robcaba]

My tank has had it's ups and downs. Most recently, major algae outbreak though it's now all looking wayyyy better. But now that the tank is recovering, these guys emerge. Any idea what they are?

 

[dougers31]

Looks like a sponge to me

 

[KJ]

^^^Agree.

 

[robcaba]

Looks like a sponge to me

Thanks dougers31. But considering I had let my tank go, would sponges not be sensitive to nitrate and amonia spikes? Unless there are "pest" sponges. I guess the question is do I leave these guys alone?

 

[reef lover]

Non invasive from what ive seen .