Can this bridsnest be saved, and strange sponge

[wareagle]

This piece was attacked by an emerald crab who is now gone. I caught him two nights ago eating algae at the base, but also occasionally picking at living tissue. I guess he went back for more after I scared him away, or the damage is spreading. There's also what looks like a regular sponge and this type with a hole in it. I've had one of these get massive and start to overgrow some GSP. Does anyone know if they're toxic and contributed to the damage? Should I scrape it off and eradicate them anytime I find them? It has slimy looking thin white skin with a single hole that I assume it eats from.

 

[Graffiti Spot]

Keep the sponges and clip the white parts off the birds nest so algae won’t grow in it. Looks like it has some polyps left in the base branch.

 

[wareagle]

thanks!