Steel ball kind of things growing in live rocks

[aloka de silva]

Hi I have a 180 gal tank with 4 T5 lights. Running a 9 hr a day.
Lionfish, 2 maroon clowns, domino damsel, 2 blue blanies, and a duoff angel.
Lots of anemones.
Few months ago I noticed some steel ball kind of thing growing on one of the rocks.
Last week there are 2 more pup up.
Please let me know this is a good signs, or what it is????
Tank is 2 yrs old.
Thanks,
Aloka

 

[benj2112]

Could be bubble algae...it can have a metalic sheen to it. Some people like it, but most would say to get rid of it if it is bubble algae.
If it is bubble algae...you don't want to pop it under water as it will really spread then. Emerald crabs will eat it. I had some and got an E crab and it eventually ate it (took a few weeks for the thing to get to the side of the tank it was on).

 

[pacopetty]

It's bubble algae. I took my rock out and used a sharp pointed knife to remove the bubbles. I did it without busting the bubbles which was a big plus.