Weird growth on live rocks

[clpotter72]

Any idea what this stuff is?

 

[Dmorty217]

Sponge, it's good

 

[Dkuhlmann]

Yep very nice sponges. They are filter feeders and very beneficial to your tank.

 

[clpotter72]

Will they continue to grow? How will they change?

 

[Dkuhlmann]

Some will some won't and they could multiply, only time will tell. By the way many species of Angelfish will eat them. The fact that you have them is a testament to how good your water parameters are.