Beautiful anemone!
I've also read a rather interesting theory that says when they bubble the expansion of the tissue allows for more area to be exposed to light. If true, that would explain the expansion under brighter lights and might be why, after eating, the bubbles deflate. They may bubble less under lower light to preserve resources similiar to sebaes which are often white with very short tentacles when stressed but after a time, exposed to proper light and food will often color up to a healthy purple/grey and the tentacles elongate to the point they look like very different anemones altogether than what you began with. Just a thought.