what is this??? good or bad??

[dirk_brijs]

hope the pictures are clear but they are like small white cocoons they look like
little teardrop shape. The feel pretty hard a bit rubbery.
2 weeks ago during cleaning I had hundreds of them in my skimmer pumps and attached to my skimmer??
Now I noticed them the first time inside the DT?
Could they be sponges? But they attach to pumps?

 

[flower]

Little sponges, filter feeders and harmless. The attach to everything. Some fish eat them. They clean the water for you so they are a good thing to have.

 

[monsinour]

those red boxes have to go. inside the boxes are sponges and they will come and go. good thing to have.