The Puffer Forum

I've attached a picture below of these odd round pink invertebrates that appeared on one of my live rocks. Not sure what they are, or if they are harmful/beneficial or what I should do with them.

Any help would be appreciated, thanks!

Whatever they are, they are a beautiful color!

Also my aquarium is riddled with feather duster worms all over the place (they are mating as we speak).
Should I start maintaining their levels, I'm worried they might cause the fish stress or deplete oxygen despite their filtering benefits.

Not sure but the pink looks like sponge. The feather dusters are excellent filter feeders, which will make your water cleaner. I've got them all over my fuge/sump.