Nobody really seems to know what triggers it. I was watching a show on Discovery where they said scientist seemed stumped by it and they thought maybe it had to do with them hosting. My green BTAs just started to bubble after 1.5 years and they barely do. My RBTA doesn't at all.
It needs a clown.
I have 5 bubble tips and my clowns use 3 of them.All three bubble,the others stay small.
I also was watching a show on coral reefs and they said the anenome's only bubble when they have a clown
My rose bubbles sometimes and sometime it doesn't
Sometimes only half of it has bubbles
No idea why