Need ID on this please.

[Breakthecycle2]

I don't know what it is. It's this long white stringy things all over my liverock. It's the best picture I could get for now.

 

[dub3]

I have them in my tank also. As ugly as they are IMO, I don't think they actually cause any harm. I believe they are just collecting food. Thy wrap around various coral in my tank and none of them ever close up.

 

[NanaReefer]

Sponge. Removed easily via siphon during WC.

 

[Breakthecycle2]

Sponge. Removed easily via siphon during WC.

Should I remove them or can i just leave them?

 

[NanaReefer]

Either or doesn't really matter. If you don't like the looks then remove them. Otherwise they are harmless filter feeders, most of which don't last long in our tanks.