What is this in my sump?

[SeanPep]

Was doing a water change this weekend and while I was cleaning out my protein skimmer I saw this. There are a few of them located in the skimmer chamber in the sump. Any ideas what it might be? Tank is about 8 months old.

[themagicman]

Sponge of some sort.

[SeanPep]

Is that good or bad? Should I remove them?

[FirstContact]

They filter the water, don't really hurt anything, some fish/cuc like to eat them, and about the only trouble you could possibly get into would be if there were a ton of them and they all died off at once.