Help identify this pest

[Mark.0015]

Hi. I've noticed a few of these pests (I assume) on my live rock. Does anybody know what they are and if I should remove them? Thank you!

 

[blaxsun]

The smaller whiteish ones on the left look like pineapple sponges (and they may in fact all be pineapple sponges). Pineapple sponges are harmless and beneficial for your tank.

 

[Mark.0015]

The smaller whiteish ones on the left look like pineapple sponges (and they may in fact all be pineapple sponges). Pineapple sponges are harmless and beneficial for your tank.

Thank you!