How/what do you feed your brain coral

[Frenchie]

Last night I caught my cleaner shrimp taking food right out of the brains mouth (and he was reaching way in there). I guess I will have to put some tupperware over the brain to let him eat.

The tentacles seem to have totaly disapeared. They used to hide under a little flap, but now even when the flap is pulled back there are no tentacles. Has anyone else ever seen this?