Small, round, fluffy, white balls appearing in aquarium

[newtoreefs]

I've noticed a few small white balls in my aquarium. One grew in size and sent out thin white strut threads to a neighboring rock. I thought it might be bad so I nabbed it with grippers and tried to pull it from the aquarium. It was attached so well, the rock lifted out of the aquarium. I managed to break it off. There are several other little balls in the aquarium. Should I be worried this?

 

[Dirtsquirt]

Sponges? Tunicates?

I've never heard of them casting webs though.

 

[newtoreefs]

Sponges? Tunicates?

I've never heard of them casting webs though.

I should have taken a picture. I'll take a picture of the smaller ones that haven't cast webs yet.

 

[Krish]

Sounds like tunicate sponges to me as well, but a pic would be helpful

 

[Herefishyfishy]

I've noticed a few small white balls in my aquarium. One grew in size and sent out thin white strut threads to a neighboring rock. I thought it might be bad so I nabbed it with grippers and tried to pull it from the aquarium. It was attached so well, the rock lifted out of the aquarium. I managed to break it off. There are several other little balls in the aquarium. Should I be worried this?

They are common and not a bad thing, filtering the water. The struts are growth patterns