What I find helps a candy cane perk up, is feeding it.
Typically I'd target feed my corals, and start with a couple of drops of oyster feast mixed with some tank water and squirt it with a syringe/eye dropper. (Make sure all your power heads and water movement equipment are off when you do this.) The oyster feast should trigger a feeding response and soon start seeing tentacles come out.
Once the sweepers are out, I then target feed with larger meatier foods (e.g. prawn eggs, mysis, chili reef, etc). Something that it can sink it's teeth into. I find that they will grab the food, retract, eat, and put their sweepers again shortly after. If they haven't eaten in a while, I'dtypically feed the same mouth a couple of times.
Once everyone has had their fill, I'll turn on the powerheads again.
Give it a shot. Like I said, you should see a feeding response within minutes.