Is this a sponge

[kenvance]

I've asked before when it was tiny but it seems to be growing out and long? There are about 6 in total with this one being the biggest. Is it a sponge or something else

 

[mr_X]

Neomeris sp. It's a macroalgae.

 

[kenvance]

So it is. Thank you very much. Ok to just leave it or get rid?

 

[mr_X]

You could leave it. If they start popping up everywhere, start plucking them.