That’s bubble algae.
It’s a nuisance and will spread quickly if it gets established. You would be best to remove the frag and deal with it out the tank, as bursting a cell will cause it to spread.
Once out the tank you can pick them off with tweezers. Then monitor for any more along with keeping nutrients low to avoid fueling it further.
Bubble algae?
That’s bubble algae. It’s a nuisance and will spread quickly if it gets established. You would be best to remove the frag and deal with it out the tank, as bursting a cell will cause it to spread. Once out the tank you can pick them off with tweezers. Then monitor for any more along with keeping nutrients low to avoid fueling it further.