Inflated brain

[ScubaSteve]

Brains are actually very active corals despite being sedentary. My brain goes through all sorts of shapes through out the day. At night it pulls in super tight but as the lights come of it opens up... and up... and up and get absolutely huge! Then through out the day it does all sorts of thing. If it eats something it closes up, then expands super big. If my hermits are ticking it off, it'll pull in. You'll start to get a feel over time of what means what when it does things... and sometimes it just does things to confuse you.

Like Matt said, as long as it looks healthy and the skeleton isn't showing you've got nothing to worry about.