Need ID 'cause you guys are good at this game

They look like bubble algae. Although I have never seen white ones before. Can you pop them or are they hard?

get rid of them ASAP!!!! They are red bubble algae. Mine would start red, dimple, cover in white then pop and spread all over the tank.

The most effective method I found was to chip off the rock they were attached to. Nothing else got rid of it.

Sort of hard, but if I squeeze hard enough, they will collapse.

+1 bubble algae

Crap!

probably shouldnt have been squeezing them lol

get that shit out of your tank now!!!! my biggest regret is leaving it in and letting it spread. its almost impossible to get rid of. i found if you make a kalkwasser paste and paste it on like aptasia it will kill it over night

What about Mithrax / emerald green crabs? Will they eat this type?

OUch..yeah...get rid of it... if something tears it - they will spread.

I like bubble algae. When I see them, I pop them.

nightmare

Update: Bone snips work well. I removed about 25% of them so far, but those were the ones that were easy to get to. Woe is me...